{"id":"CVE-2026-3549","aliases":["ALPINE-CVE-2026-3549","DEBIAN-CVE-2026-3549","EUVD-2026-13168","GHSA-j2g5-52p7-mfpc","JLSEC-2026-708","UBUNTU-CVE-2026-3549"],"status":"published","title":"ECH parsing heap buffer overflow","description":"Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.","severity":{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00507,"percentile":0.43538,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-122"],"published":"2026-03-19T20:09:27Z","modified":"2026-11-03T06:33:02Z","fixes":[{"ecosystem":"Alpine:v3.23","package":"wolfssl","fixed_in":["5.9.1-r0"],"sources":["osv"]},{"ecosystem":"Alpine:v3.24","package":"wolfssl","fixed_in":["5.9.0-r0"],"sources":["osv"]},{"ecosystem":"Julia","package":"wolfSSL_jll","fixed_in":["5.9.2+0"],"sources":["osv"]}],"affected":[{"source":"osv","ecosystem":"Alpine:v3.23","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.9.1-r0"}]}]},{"source":"osv","ecosystem":"Alpine:v3.24","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"5.9.0-r0"}]}]},{"source":"osv","ecosystem":"Debian:12","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.5.4-2","5.5.4-2+deb12u1","5.5.4-2+deb12u2","5.5.4-2+deb12u3","5.5.4-2.1","5.6.4-1","5.6.4-2","5.6.6-1","5.6.6-1.1","5.6.6-1.2","5.6.6-1.3","5.6.6-1.3~exp1","5.7.0-0.1","5.7.0-0.2","5.7.0-0.3","5.7.2-0.1","5.7.2-0.2","5.7.2-0.3","5.7.2-0.4","5.8.2-1","5.8.2-1.1","5.8.2-1.2","5.8.4-1","5.9.0-0.1","5.9.0-0.2","5.9.1-0.1","5.9.2-1"]},{"source":"osv","ecosystem":"Debian:13","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.7.2-0.1","5.7.2-0.1+deb13u1","5.7.2-0.1+deb13u2","5.7.2-0.2","5.7.2-0.3","5.7.2-0.4","5.8.2-1","5.8.2-1.1","5.8.2-1.2","5.8.4-1","5.9.0-0.1","5.9.0-0.2","5.9.1-0.1","5.9.2-1"]},{"source":"osv","ecosystem":"Julia","package":"wolfSSL_jll","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"fixed":"5.9.2+0"}]}]},{"source":"osv","ecosystem":"Ubuntu:16.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.4.8+dfsg-1"]},{"source":"osv","ecosystem":"Ubuntu:18.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.10.2+dfsg-2","3.12.0+dfsg-1","3.12.2+dfsg-1","3.13.0+dfsg-1"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.1.0+dfsg-2","4.2.0+dfsg-1","4.2.0+dfsg-2","4.2.0+dfsg-3","4.3.0+dfsg-2"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["4.6.0-3","5.0.0-1","5.1.1-1","5.2.0-1","5.2.0-2"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.5.4-2","5.5.4-2.1","5.6.4-2","5.6.6-1.2","5.6.6-1.3","5.6.6-1.3build1"]},{"source":"osv","ecosystem":"Ubuntu:25.10","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.7.2-0.1"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.9.1-0.1","5.9.2-1"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"wolfssl","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.7.2-0.1","5.8.2-1.2","5.8.4-1","5.9.1-0.1"]}],"products":[{"vendor":"wofssl","product":"wolfssl"},{"vendor":"wolfssl","product":"wolfssl"}],"references":[{"url":"https://github.com/wolfSSL/wolfssl/pull/9817","tags":["Issue Tracking","Patch","fix","web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-3549","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-j2g5-52p7-mfpc"},{"url":"https://security.alpinelinux.org/vuln/CVE-2026-3549","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/3xxx/CVE-2026-3549.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-3549","tags":["advisory"]},{"url":"https://ubuntu.com/security/CVE-2026-3549","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-3549","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-3549","title":"ECH parsing heap buffer overflow","description":"Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.","status":"published","published":"2026-03-19T20:09:27.036Z","modified":"2026-03-24T01:38:13.951Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L","level":"high","assessor":"cna"}],"cwes":["CWE-122"],"updated_at":"2026-11-02T13:48:58.05327Z"}],"euvd":[{"id":"EUVD-2026-13168","description":"Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.","status":"published","published":"2026-03-19T20:09:27Z","modified":"2026-03-24T01:38:13Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L","level":"high"}],"updated_at":"2026-11-02T19:25:30.696372Z"}],"ghsa":[{"id":"GHSA-j2g5-52p7-mfpc","title":"Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic...","description":"Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.","status":"published","published":"2026-03-19T21:30:25Z","modified":"2026-03-26T18:32:30Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"cwes":["CWE-122"],"updated_at":"2026-11-02T15:06:53.526079Z"}],"nvd":[{"id":"CVE-2026-3549","description":"Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.","status":"published","published":"2026-03-19T21:17:12.823Z","modified":"2026-06-17T10:43:46.21Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"high","assessor":"secondary"},{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical","assessor":"primary"}],"cwes":["CWE-122"],"updated_at":"2026-11-02T14:12:09.735529Z"}],"osv":[{"id":"ALPINE-CVE-2026-3549","description":"Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.","status":"published","published":"2026-03-19T21:17:12.823Z","modified":"2026-11-03T06:33:02.451240391Z","cvss":[{"version":"3.1","score":9.8,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","level":"critical"}],"updated_at":"2026-11-03T07:15:53.944853Z"},{"id":"CVE-2026-3549","title":"ECH parsing heap buffer overflow","description":"Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. Note that in wolfSSL, ECH is off by default, and the ECH standard is still evolving.","status":"published","published":"2026-03-19T20:09:27.036Z","modified":"2026-10-28T02:30:25.502411986Z","cvss":[{"version":"4.0","score":8.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/VA:H/SC:L/SI:L/SA:L","level":"high"}],"cwes":["CWE-122"],"updated_at":"2026-11-02T15:45:02.673625Z"},{"id":"DEBIAN-CVE-2026-3549","description":"Heap Overflow in TLS 1.3 ECH parsing. An integer underflow existed in ECH extension parsing logic when calculating a buffer length, which resulted in writing beyond the bounds of an allocated buffer. 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