{"id":"CVE-2026-40686","aliases":["ALPINE-CVE-2026-40686","CLSA-2026-1778690918","CLSA-2026-1779369819","CLSA-2026-1780519410","DEBIAN-CVE-2026-40686","EUVD-2026-26444","GHSA-f965-ghfw-x6jx","UBUNTU-CVE-2026-40686","USN-8382-1"],"status":"published","title":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large...","description":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.","severity":{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-10","score":0.00246,"percentile":0.15986,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-125"],"published":"2026-04-29T12:00:00Z","modified":"2026-11-03T06:32:55Z","fixes":[{"ecosystem":"Alpine:v3.23","package":"exim","fixed_in":["4.98.2-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.24","package":"exim","fixed_in":["4.98.2-r0"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim","fixed_in":["4.99.1-1.el9.tuxcare.els3"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim-greylist","fixed_in":["4.99.1-1.el9.tuxcare.els3"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim-mon","fixed_in":["4.99.1-1.el9.tuxcare.els3"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim-mysql","fixed_in":["4.99.1-1.el9.tuxcare.els3"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim-pgsql","fixed_in":["4.99.1-1.el9.tuxcare.els3"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim","fixed_in":["4.99.1-1.el9_2.tuxcare.els2"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim-greylist","fixed_in":["4.99.1-1.el9_2.tuxcare.els2"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim-mon","fixed_in":["4.99.1-1.el9_2.tuxcare.els2"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim-mysql","fixed_in":["4.99.1-1.el9_2.tuxcare.els2"],"sources":["osv"]},{"ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim-pgsql","fixed_in":["4.99.1-1.el9_2.tuxcare.els2"],"sources":["osv"]},{"ecosystem":"Debian:12","package":"exim4","fixed_in":["4.96-15+deb12u9"],"sources":["osv"]},{"ecosystem":"Debian:13","package":"exim4","fixed_in":["4.98.2-1+deb13u2"],"sources":["osv"]},{"ecosystem":"Debian:14","package":"exim4","fixed_in":["4.99.2-1"],"sources":["osv"]},{"ecosystem":"Ubuntu:Pro:20.04:LTS","package":"exim4","fixed_in":["4.93-13ubuntu1.12+esm1"],"sources":["osv"]},{"ecosystem":"Ubuntu:22.04:LTS","package":"exim4","fixed_in":["4.95-4ubuntu2.7"],"sources":["osv"]},{"ecosystem":"Ubuntu:24.04:LTS","package":"exim4","fixed_in":["4.97-4ubuntu4.4"],"sources":["osv"]},{"ecosystem":"Ubuntu:25.10","package":"exim4","fixed_in":["4.98.2-1ubuntu2.1"],"sources":["osv"]},{"ecosystem":"Ubuntu:26.04:LTS","package":"exim4","fixed_in":["4.99.1-1ubuntu1.1"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Alpine:v3.23","package":"exim","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.98.2-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.24","package":"exim","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.98.2-r0"}]}]},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9.tuxcare.els3"}]}]},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim-greylist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9.tuxcare.els3"}]}]},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim-mon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9.tuxcare.els3"}]}]},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim-mysql","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9.tuxcare.els3"}]}]},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.6","package":"exim-pgsql","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9.tuxcare.els3"}]}]},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.90.1-1ubuntu1.10+tuxcare.els6"}]}],"bundled":2},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"exim4-base","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.90.1-1ubuntu1.10+tuxcare.els6"}]}],"bundled":2},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"exim4-config","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.90.1-1ubuntu1.10+tuxcare.els6"}]}],"bundled":2},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"exim4-daemon-heavy","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.90.1-1ubuntu1.10+tuxcare.els6"}]}],"bundled":2},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"exim4-daemon-light","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.90.1-1ubuntu1.10+tuxcare.els6"}]}],"bundled":2},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"exim4-dev","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.90.1-1ubuntu1.10+tuxcare.els6"}]}],"bundled":2},{"source":"osv","ecosystem":"TuxCare:Ubuntu:18.04","package":"eximon4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.90.1-1ubuntu1.10+tuxcare.els6"}]}],"bundled":2},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9_2.tuxcare.els2"}]}]},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim-greylist","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9_2.tuxcare.els2"}]}]},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim-mon","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9_2.tuxcare.els2"}]}]},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim-mysql","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9_2.tuxcare.els2"}]}]},{"source":"osv","ecosystem":"TuxCare:AlmaLinux:9.2","package":"exim-pgsql","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1.el9_2.tuxcare.els2"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.96-15+deb12u9"}]}],"versions":["4.96-15","4.96-15+deb12u1","4.96-15+deb12u2","4.96-15+deb12u3","4.96-15+deb12u4","4.96-15+deb12u5","4.96-15+deb12u6","4.96-15+deb12u7","4.96-15+deb12u8"]},{"source":"osv","ecosystem":"Debian:13","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.98.2-1+deb13u2"}]}],"versions":["4.98.2-1","4.98.2-1+deb13u1"]},{"source":"osv","ecosystem":"Debian:14","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.2-1"}]}],"versions":["4.98.2-1","4.98.2-1+hurd.1","4.98.2-2","4.99-1","4.99-2","4.99-3","4.99-4","4.99-4~bpo13+1","4.99-5","4.99-6","4.99-6~bpo13+1","4.99-7","4.99-7~bpo13+1","4.99.1-1","4.99.1-1~bpo13+1","4.99.1-2","4.99.1-3","4.99.1-4","4.99.1-5","4.99.1-6","4.99.2-1~bpo13+1","4.99~RC1-1","4.99~RC2-1","4.99~RC3-1","4.99~RC3-2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:14.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.80-7ubuntu3","4.80-7ubuntu4","4.80-9ubuntu1","4.80-9ubuntu2","4.82-3ubuntu1","4.82-3ubuntu2","4.82-3ubuntu2.1","4.82-3ubuntu2.2","4.82-3ubuntu2.3","4.82-3ubuntu2.4","4.82-3ubuntu2.4+esm1","4.82-3ubuntu2.4+esm2","4.82-3ubuntu2.4+esm3","4.82-3ubuntu2.4+esm4","4.82-3ubuntu2.4+esm6","4.82-3ubuntu2.4+esm7","4.82-3ubuntu2.4+esm8","4.82-3ubuntu2.4+esm9"]},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.86-3ubuntu1","4.86-7ubuntu1","4.86-7ubuntu2","4.86-7ubuntu3","4.86.2-2ubuntu1","4.86.2-2ubuntu2","4.86.2-2ubuntu2.1","4.86.2-2ubuntu2.2","4.86.2-2ubuntu2.3","4.86.2-2ubuntu2.4","4.86.2-2ubuntu2.5","4.86.2-2ubuntu2.6","4.86.2-2ubuntu2.6+esm1","4.86.2-2ubuntu2.6+esm2","4.86.2-2ubuntu2.6+esm4","4.86.2-2ubuntu2.6+esm5","4.86.2-2ubuntu2.6+esm6","4.86.2-2ubuntu2.6+esm7","4.86.2-2ubuntu2.6+esm8","4.86.2-2ubuntu2.6+esm9"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.89-5ubuntu1","4.89-9ubuntu1","4.89-9ubuntu2","4.89-9ubuntu3","4.89-9ubuntu4","4.90.1-1ubuntu1","4.90.1-1ubuntu1.1","4.90.1-1ubuntu1.2","4.90.1-1ubuntu1.3","4.90.1-1ubuntu1.4","4.90.1-1ubuntu1.5","4.90.1-1ubuntu1.8","4.90.1-1ubuntu1.9","4.90.1-1ubuntu1.10","4.90.1-1ubuntu1.10+esm1","4.90.1-1ubuntu1.10+esm2","4.90.1-1ubuntu1.10+esm3","4.90.1-1ubuntu1.10+esm4","4.90.1-1ubuntu1.10+esm5","4.90.1-1ubuntu1.10+esm6"]},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.93-13ubuntu1.12+esm1"}]}],"versions":["4.92.1-1ubuntu3","4.92.1-1ubuntu4","4.93~RC2-1ubuntu1","4.93-9ubuntu1","4.93-11ubuntu1","4.93-12ubuntu1","4.93-13ubuntu1","4.93-13ubuntu1.1","4.93-13ubuntu1.5","4.93-13ubuntu1.6","4.93-13ubuntu1.7","4.93-13ubuntu1.8","4.93-13ubuntu1.9","4.93-13ubuntu1.10","4.93-13ubuntu1.11","4.93-13ubuntu1.12"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.95-4ubuntu2.7"}]}],"versions":["4.94.2-7ubuntu2","4.95-2ubuntu2","4.95-4ubuntu1","4.95-4ubuntu2","4.95-4ubuntu2.1","4.95-4ubuntu2.2","4.95-4ubuntu2.3","4.95-4ubuntu2.4","4.95-4ubuntu2.5","4.95-4ubuntu2.6"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.97-4ubuntu4.4"}]}],"versions":["4.96-17ubuntu2","4.96-17ubuntu2.1","4.97-3ubuntu1","4.97-4ubuntu1","4.97-4ubuntu3","4.97-4ubuntu4","4.97-4ubuntu4.1","4.97-4ubuntu4.2","4.97-4ubuntu4.3"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.98.2-1ubuntu2.1"}]}],"versions":["4.98.1-1ubuntu2","4.98.2-1ubuntu1","4.98.2-1ubuntu2"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.99.1-1ubuntu1.1"}]}],"versions":["4.98.2-1ubuntu2","4.99-4ubuntu1","4.99.1-1ubuntu1"]},{"source":"osv","ecosystem":"Ubuntu:Pro:14.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.82-3ubuntu2.4+esm9"}]}],"versions":["4.80-7ubuntu3","4.80-7ubuntu4","4.80-9ubuntu1","4.80-9ubuntu2","4.82-3ubuntu1","4.82-3ubuntu2","4.82-3ubuntu2.1","4.82-3ubuntu2.2","4.82-3ubuntu2.3","4.82-3ubuntu2.4","4.82-3ubuntu2.4+esm1","4.82-3ubuntu2.4+esm2","4.82-3ubuntu2.4+esm3","4.82-3ubuntu2.4+esm4","4.82-3ubuntu2.4+esm6","4.82-3ubuntu2.4+esm7","4.82-3ubuntu2.4+esm8"],"bundled":6},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.86.2-2ubuntu2.6+esm9"}]}],"versions":["4.86-3ubuntu1","4.86-7ubuntu1","4.86-7ubuntu2","4.86-7ubuntu3","4.86.2-2ubuntu1","4.86.2-2ubuntu2","4.86.2-2ubuntu2.1","4.86.2-2ubuntu2.2","4.86.2-2ubuntu2.3","4.86.2-2ubuntu2.4","4.86.2-2ubuntu2.5","4.86.2-2ubuntu2.6","4.86.2-2ubuntu2.6+esm1","4.86.2-2ubuntu2.6+esm2","4.86.2-2ubuntu2.6+esm4","4.86.2-2ubuntu2.6+esm5","4.86.2-2ubuntu2.6+esm6","4.86.2-2ubuntu2.6+esm7","4.86.2-2ubuntu2.6+esm8"],"bundled":6},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.90.1-1ubuntu1.10+esm6"}]}],"versions":["4.89-5ubuntu1","4.89-9ubuntu1","4.89-9ubuntu2","4.89-9ubuntu3","4.89-9ubuntu4","4.90.1-1ubuntu1","4.90.1-1ubuntu1.1","4.90.1-1ubuntu1.2","4.90.1-1ubuntu1.3","4.90.1-1ubuntu1.4","4.90.1-1ubuntu1.5","4.90.1-1ubuntu1.8","4.90.1-1ubuntu1.9","4.90.1-1ubuntu1.10","4.90.1-1ubuntu1.10+esm1","4.90.1-1ubuntu1.10+esm2","4.90.1-1ubuntu1.10+esm3","4.90.1-1ubuntu1.10+esm4","4.90.1-1ubuntu1.10+esm5"],"bundled":6},{"source":"osv","ecosystem":"Ubuntu:Pro:20.04:LTS","package":"exim4","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"4.93-13ubuntu1.12+esm1"}]}],"versions":["4.92.1-1ubuntu3","4.92.1-1ubuntu4","4.93~RC2-1ubuntu1","4.93-9ubuntu1","4.93-11ubuntu1","4.93-12ubuntu1","4.93-13ubuntu1","4.93-13ubuntu1.1","4.93-13ubuntu1.5","4.93-13ubuntu1.6","4.93-13ubuntu1.7","4.93-13ubuntu1.8","4.93-13ubuntu1.9","4.93-13ubuntu1.10","4.93-13ubuntu1.11","4.93-13ubuntu1.12"],"bundled":6}],"products":[{"vendor":"exim","product":"exim"}],"references":[{"url":"https://www.openwall.com/lists/oss-security/2026/04/30/21","tags":["Mailing List","Third Party Advisory"]},{"url":"https://exim.org/static/doc/security/cve-2026-04.1/CVE2026-40686.assessment","tags":["Vendor Advisory"]},{"url":"https://code.exim.org/exim/exim/commit/f2570bde16fb4d4a1242ff363a4c4eecf6372efc","tags":["Patch"]},{"url":"https://exim.org/static/doc/security/CVE-2026-40686.txt","tags":["Broken Link"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-40686","tags":["advisory"]},{"url":"https://exim.org/static/doc/security/CVE-2025-40686.txt"},{"url":"https://github.com/advisories/GHSA-f965-ghfw-x6jx"},{"url":"https://security.alpinelinux.org/vuln/CVE-2026-40686","tags":["advisory"]},{"url":"https://errata.tuxcare.com/els_os/tuxcare9.6esu/CLSA-2026-1778690918.html","tags":["advisory"]},{"url":"https://errata.tuxcare.com/els_os/ubuntu18.04els/CLSA-2026-1779369819.html","tags":["advisory"]},{"url":"https://errata.tuxcare.com/els_os/almalinux9.2esu/CLSA-2026-1780519410.html","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-40686","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-40686","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-40686","tags":["report"]},{"url":"https://lists.exim.org/lurker/message/20260429.121733.f58d9686.en.html","tags":["report"]},{"url":"https://ubuntu.com/security/notices/USN-8228-1","tags":["advisory"]},{"url":"https://ubuntu.com/security/notices/USN-8382-1","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2023-51766","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2026-40685","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2026-40687","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2026-45185","tags":["report"]},{"url":"https://ubuntu.com/security/CVE-2026-48840","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-40686","description":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.","status":"published","published":"2026-04-30T00:00:00Z","modified":"2026-05-01T14:27:11.39Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"cna"}],"cwes":["CWE-125"],"updated_at":"2026-11-02T13:43:11.445168Z"}],"euvd":[{"id":"EUVD-2026-26444","description":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.","status":"published","published":"2026-04-30T00:00:00Z","modified":"2026-05-01T14:27:11Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"updated_at":"2026-11-02T19:05:18.723006Z"}],"ghsa":[{"id":"GHSA-f965-ghfw-x6jx","title":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large...","description":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.","status":"published","published":"2026-05-01T00:31:27Z","modified":"2026-05-01T03:31:23Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"}],"cwes":["CWE-125"],"updated_at":"2026-11-02T15:07:52.84276Z"}],"nvd":[{"id":"CVE-2026-40686","description":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.","status":"published","published":"2026-04-30T22:16:25.787Z","modified":"2026-06-17T10:45:34.447Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low","assessor":"secondary"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium","assessor":"primary"}],"cwes":["CWE-125"],"updated_at":"2026-11-02T14:12:16.626888Z"}],"osv":[{"id":"ALPINE-CVE-2026-40686","description":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.","status":"published","published":"2026-04-30T22:16:25.787Z","modified":"2026-11-03T06:32:55.441473884Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-03T07:16:26.770911Z"},{"id":"DEBIAN-CVE-2026-40686","description":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.","status":"published","published":"2026-04-30T22:16:25.787Z","modified":"2026-10-01T03:03:04.760990612Z","cvss":[{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T15:45:54.892385Z"},{"id":"UBUNTU-CVE-2026-40686","description":"In Exim before 4.99.2, when utf8 operators are enabled, there is an out-of-bounds read if large UTF-8 trailing characters are present (malformed UTF-8 header data). Information might be divulged within an error message produced during handling of an unrelated e-mail message.","status":"published","published":"2026-04-29T12:00:00Z","modified":"2026-06-04T02:14:18.899101076Z","cvss":[{"version":"3.1","score":3.7,"vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"low"},{"version":"3.1","score":5.3,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N","level":"medium"}],"updated_at":"2026-11-02T16:56:16.686388Z"},{"id":"CLSA-2026-1778690918","title":"exim: Fix of CVE-2026-40686","description":"- CVE-2026-40686: out-of-bounds read in the GETUTF8INC macro in src/expand.c\n  when processing malformed UTF-8 in expansion operators with utf8 enabled,\n  potentially disclosing heap data via SMTP rejection messages.","status":"published","published":"2026-05-13T16:48:43Z","modified":"2026-06-01T00:32:52.276276269Z","updated_at":"2026-11-02T15:43:44.737408Z"},{"id":"CLSA-2026-1779369819","title":"Fix CVE(s): CVE-2026-40686, CVE-2026-40687","description":"   * SECURITY UPDATE: heap read out-of-bounds in UTF-8 expansion\n     - debian/patches/CVE-2026-40686.patch: harden ${from_utf8:} expansion\n       operator against malformed UTF-8 trailing bytes.\n     - CVE-2026-40686\n   * SECURITY UPDATE: SPA authenticator buffer hardening\n     - debian/patches/CVE-2026-40687.patch: zero spa_base64_to_bits output\n       buffer and replace static 1024-byte buffers in unicodeToString,\n       strToUnicode, toString with dynamic store_get allocations sized to\n       input.\n     - CVE-2026-40687","status":"published","published":"2026-05-21T13:23:43Z","modified":"2026-06-04T10:03:35.366027Z","updated_at":"2026-11-02T15:43:45.090939Z"},{"id":"CLSA-2026-1780519410","title":"exim: Fix of CVE-2026-40686","description":"- CVE-2026-40686: out-of-bounds heap read in GETUTF8INC macro when utf8\n  operators process malformed input; may exfiltrate heap data via SMTP\n  rejection messages","status":"published","published":"2026-06-03T20:43:42Z","modified":"2026-10-26T09:30:17.585187594Z","updated_at":"2026-11-02T15:43:45.445699Z"},{"id":"USN-8382-1","title":"exim4 vulnerabilities","description":"Timo Longin discovered that Exim incorrectly handled certain SMTP messages\nin PIPELINING/CHUNKING configurations. A remote attacker could possibly use\nthis issue to perform SMTP smuggling. This issue only affected Ubuntu\n14.04 LTS. (CVE-2023-51766)\n\nIt was discovered that Exim incorrectly handled certain malformed JSON\ndata in headers. A remote attacker could possibly use this issue to crash\nExim, resulting in a denial of service, or execute arbitrary code. This\nissue only affected Ubuntu 20.04 LTS. (CVE-2026-40685)\n\nIt was discovered that Exim incorrectly handled certain malformed UTF-8\nheaders. A remote attacker could possibly use this issue to obtain\nsensitive information. This issue only affected Ubuntu 20.04 LTS.\n(CVE-2026-40686)\n\nIt was discovered that Exim incorrectly handled certain SPA resources.\nA remote attacker could possibly use this issue to crash Exim, resulting in\na denial of service, or obtain sensitive information. This issue only\naffected Ubuntu 20.04 LTS. (CVE-2026-40687)\n\nIt was discovered that Exim incorrectly handled certain CHUNKING\ntransfers in some GnuTLS configurations. A remote attacker could possibly\nuse this issue to crash Exim, resulting in a denial of service, or execute\narbitrary code. This issue only affected Ubuntu 20.04 LTS. (CVE-2026-45185)\n\nWarisjeet Singh discovered that Exim incorrectly handled certain proxy\nconnections in builds with proxy support enabled. A remote attacker could\npossibly use this issue to obtain sensitive information. This issue only\naffected Ubuntu 16.04 LTS, Ubuntu 18.04 LTS, and Ubuntu 20.04 LTS.\n(CVE-2026-48840)","status":"published","published":"2026-06-03T16:29:23Z","modified":"2026-06-04T02:18:10.818665128Z","updated_at":"2026-11-02T16:58:25.103481Z"}]}}