{"id":"CVE-2026-102997","aliases":["CLSA-2026-1791448168","DEBIAN-CVE-2026-102997","EUVD-2026-90373","GHSA-jw7q-gvrg-4vj3","PYSEC-2026-4156","UBUNTU-CVE-2026-102997"],"status":"published","title":"pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)","description":"pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.","severity":{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-11","score":0.0034,"percentile":0.27878,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":true},"cwes":["CWE-400","CWE-407"],"published":"2026-09-30T20:05:51Z","modified":"2026-11-04T02:47:05Z","fixes":[{"ecosystem":"PyPI","package":"pypdf","fixed_in":["6.18.1"],"sources":["ghsa","osv"]},{"ecosystem":"Debian:14","package":"pypdf","fixed_in":["6.19.0-1"],"sources":["osv"]}],"affected":[{"source":"ghsa","ecosystem":"PyPI","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.18.1"}]}]},{"source":"osv","ecosystem":"TuxCare:PyPI","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.9.0"},{"fixed":"5.9.0.post19+tuxcare"}]}],"versions":["5.9.0","5.9.0.post1+tuxcare","5.9.0.post10+tuxcare","5.9.0.post11+tuxcare","5.9.0.post12+tuxcare","5.9.0.post13+tuxcare","5.9.0.post14+tuxcare","5.9.0.post15+tuxcare","5.9.0.post16+tuxcare","5.9.0.post17+tuxcare","5.9.0.post18+tuxcare","5.9.0.post2+tuxcare","5.9.0.post3+tuxcare","5.9.0.post4+tuxcare","5.9.0.post5+tuxcare","5.9.0.post6+tuxcare","5.9.0.post7+tuxcare","5.9.0.post8+tuxcare","5.9.0.post9+tuxcare"],"bundled":3},{"source":"osv","ecosystem":"Debian:12","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.17.4-1","3.4.1-1","3.4.1-1+deb12u1","4.0.0-1","4.0.0-1~exp1","4.0.1-1","4.0.2-1","4.1.0-1","4.2.0-1","4.3.1-1","5.4.0-1","6.19.0-1","6.21.0-1","6.21.1-1","6.21.4-1","6.9.0-1","6.9.2-1","6.9.2-2"]},{"source":"osv","ecosystem":"Debian:13","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.4.0-1","6.19.0-1","6.21.0-1","6.21.1-1","6.21.4-1","6.9.0-1","6.9.2-1","6.9.2-2"]},{"source":"osv","ecosystem":"Debian:14","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.19.0-1"}]}],"versions":["5.4.0-1","6.9.0-1","6.9.2-1","6.9.2-2"]},{"source":"osv","ecosystem":"Debian:12","package":"pypdf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.12.1-3","2.12.1-3+deb12u1","2.12.1-4"]},{"source":"osv","ecosystem":"PyPI","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.18.1"}]}],"versions":["1.0","1.1","1.10","1.11","1.12","1.13","1.2","1.3","1.4","1.5","1.6","1.7","1.8","1.9","3.1.0","3.10.0","3.11.0","3.11.1","3.12.0","3.12.1","3.12.2","3.13.0","3.14.0","3.15.0","3.15.1","3.15.2","3.15.3","3.15.4","3.15.5","3.16.0","3.16.1","3.16.2","3.16.3","3.16.4","3.17.0","3.17.1","3.17.2","3.17.3","3.17.4","3.2.0","3.2.1","3.3.0","3.4.0","3.4.1","3.5.0","3.5.1","3.5.2","3.6.0","3.7.0","3.7.1","3.8.0","3.8.1","3.9.0","3.9.1","4.0.0","4.0.1","4.0.2","4.1.0","4.2.0","4.3.0","4.3.1","5.0.0","5.0.1","5.1.0","5.2.0","5.3.0","5.3.1","5.4.0","5.5.0","5.6.0","5.6.1","5.7.0","5.8.0","5.9.0","6.0.0","6.1.0","6.1.1","6.1.2","6.1.3","6.10.0","6.10.1","6.10.2","6.11.0","6.12.0","6.12.1","6.12.2","6.13.0","6.13.1","6.13.2","6.13.3","6.14.0","6.14.1","6.14.2","6.15.0","6.16.0","6.16.1","6.16.2","6.17.0","6.18.0","6.2.0","6.3.0","6.4.0","6.4.1","6.4.2","6.5.0","6.6.0","6.6.1","6.6.2","6.7.0","6.7.1","6.7.2","6.7.3","6.7.4","6.7.5","6.8.0","6.9.0","6.9.1","6.9.2"]},{"source":"osv","ecosystem":"PyPI","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"6.18.1"}]}],"versions":["1.0","1.1","1.10","1.11","1.12","1.13","1.2","1.3","1.4","1.5","1.6","1.7","1.8","1.9","3.1.0","3.10.0","3.11.0","3.11.1","3.12.0","3.12.1","3.12.2","3.13.0","3.14.0","3.15.0","3.15.1","3.15.2","3.15.3","3.15.4","3.15.5","3.16.0","3.16.1","3.16.2","3.16.3","3.16.4","3.17.0","3.17.1","3.17.2","3.17.3","3.17.4","3.2.0","3.2.1","3.3.0","3.4.0","3.4.1","3.5.0","3.5.1","3.5.2","3.6.0","3.7.0","3.7.1","3.8.0","3.8.1","3.9.0","3.9.1","4.0.0","4.0.1","4.0.2","4.1.0","4.2.0","4.3.0","4.3.1","5.0.0","5.0.1","5.1.0","5.2.0","5.3.0","5.3.1","5.4.0","5.5.0","5.6.0","5.6.1","5.7.0","5.8.0","5.9.0","6.0.0","6.1.0","6.1.1","6.1.2","6.1.3","6.10.0","6.10.1","6.10.2","6.11.0","6.12.0","6.12.1","6.12.2","6.13.0","6.13.1","6.13.2","6.13.3","6.14.0","6.14.1","6.14.2","6.15.0","6.16.0","6.16.1","6.16.2","6.17.0","6.18.0","6.2.0","6.3.0","6.4.0","6.4.1","6.4.2","6.5.0","6.6.0","6.6.1","6.6.2","6.7.0","6.7.1","6.7.2","6.7.3","6.7.4","6.7.5","6.8.0","6.9.0","6.9.1","6.9.2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:16.04:LTS","package":"pypdf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.23+git20141008-1","1.25.1-1","1.25.1-1ubuntu0.1~esm1","1.25.1-1ubuntu0.1~esm2"]},{"source":"osv","ecosystem":"Ubuntu:Pro:18.04:LTS","package":"pypdf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.26.0-2","1.26.0-2ubuntu0.1~esm1","1.26.0-2ubuntu0.1~esm2"]},{"source":"osv","ecosystem":"Ubuntu:20.04:LTS","package":"pypdf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.26.0-2","1.26.0-3ubuntu1","1.26.0-3ubuntu1.20.04.1","1.26.0-3ubuntu1.20.04.2"]},{"source":"osv","ecosystem":"Ubuntu:22.04:LTS","package":"pypdf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["1.26.0-4","1.26.0-4ubuntu0.22.04.1","1.26.0-4ubuntu0.22.04.2"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["3.4.1-1","3.17.4-1","4.0.0-1","4.0.1-1","4.0.2-1"]},{"source":"osv","ecosystem":"Ubuntu:24.04:LTS","package":"pypdf2","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["2.12.1-3","2.12.1-4"]},{"source":"osv","ecosystem":"Ubuntu:26.10","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["6.9.2-1","6.9.2-2"]},{"source":"osv","ecosystem":"Ubuntu:26.04:LTS","package":"pypdf","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}],"versions":["5.4.0-1","6.9.2-1"]}],"products":[{"vendor":"py-pdf","product":"pypdf"}],"references":[{"url":"https://github.com/py-pdf/pypdf/security/advisories/GHSA-jw7q-gvrg-4vj3","tags":["x_refsource_CONFIRM","Vendor Advisory","advisory","web","report"]},{"url":"https://github.com/py-pdf/pypdf/pull/4073","tags":["x_refsource_MISC","Patch","Issue Tracking","fix","web","report"]},{"url":"https://github.com/py-pdf/pypdf/commit/d9d38cf99b115deb562d3b68f36c33027bc04f79","tags":["x_refsource_MISC","Patch","fix","web","report"]},{"url":"https://github.com/py-pdf/pypdf/releases/tag/6.18.1","tags":["x_refsource_MISC","Release Notes","web","report"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-102997","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-jw7q-gvrg-4vj3","tags":["advisory"]},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/102xxx/CVE-2026-102997.json","tags":["advisory"]},{"url":"https://security-tracker.debian.org/tracker/CVE-2026-102997","tags":["advisory"]},{"url":"https://github.com/py-pdf/pypdf","tags":["package"]},{"url":"https://pypi.org/project/pypdf","tags":["package"]},{"url":"https://ubuntu.com/security/CVE-2026-102997","tags":["report"]},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-102997","tags":["report"]}],"sources":{"cve":[{"id":"CVE-2026-102997","title":"pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)","description":"pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.","status":"published","published":"2026-09-30T20:05:51.538Z","modified":"2026-10-02T16:33:34.257Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high","assessor":"cna"}],"cwes":["CWE-400","CWE-407"],"updated_at":"2026-11-02T13:38:54.394896Z"}],"euvd":[{"id":"EUVD-2026-90373","description":"pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.","status":"published","published":"2026-09-30T20:05:51Z","modified":"2026-10-02T16:33:34Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T17:27:42.693498Z"}],"ghsa":[{"id":"GHSA-jw7q-gvrg-4vj3","title":"pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)","description":"### Impact\n\nAn attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a partially malformed `/FlateDecode` stream, where the byte-by-byte decompression is used.\n\n### Patches\n\nThis has been fixed in [pypdf==6.18.1](https://github.com/py-pdf/pypdf/releases/tag/6.18.1).\n\n### Workarounds\n\nIf you cannot upgrade yet, consider applying the changes from PR [#4073](https://github.com/py-pdf/pypdf/pull/4073).","status":"published","published":"2026-10-01T15:06:33Z","modified":"2026-10-01T15:06:34Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-400","CWE-407"],"updated_at":"2026-11-02T14:41:23.783773Z"}],"nvd":[{"id":"CVE-2026-102997","description":"pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.","status":"published","published":"2026-09-30T21:17:07.02Z","modified":"2026-11-02T16:06:04.477Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/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":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high","assessor":"primary"}],"cwes":["CWE-400","CWE-407"],"updated_at":"2026-11-02T20:51:41.281615Z"}],"osv":[{"id":"CVE-2026-102997","title":"pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)","description":"pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.","status":"published","published":"2026-09-30T20:05:51.538Z","modified":"2026-11-04T02:47:05.407086036Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-400","CWE-407"],"updated_at":"2026-11-04T02:53:57.551196Z"},{"id":"DEBIAN-CVE-2026-102997","description":"pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.","status":"published","published":"2026-09-30T21:17:07.02Z","modified":"2026-11-03T10:00:30.217539049Z","cvss":[{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-03T10:27:58.933618Z"},{"id":"GHSA-jw7q-gvrg-4vj3","title":"pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)","description":"### Impact\n\nAn attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a partially malformed `/FlateDecode` stream, where the byte-by-byte decompression is used.\n\n### Patches\n\nThis has been fixed in [pypdf==6.18.1](https://github.com/py-pdf/pypdf/releases/tag/6.18.1).\n\n### Workarounds\n\nIf you cannot upgrade yet, consider applying the changes from PR [#4073](https://github.com/py-pdf/pypdf/pull/4073).","status":"published","published":"2026-10-01T15:06:33Z","modified":"2026-10-01T17:56:11.608019455Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"cwes":["CWE-400","CWE-407"],"updated_at":"2026-11-02T15:46:51.10002Z"},{"id":"PYSEC-2026-4156","title":"pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)","description":"### Impact\n\nAn attacker who uses this vulnerability can craft a PDF which leads to long runtimes. This requires a partially malformed `/FlateDecode` stream, where the byte-by-byte decompression is used.\n\n### Patches\n\nThis has been fixed in [pypdf==6.18.1](https://github.com/py-pdf/pypdf/releases/tag/6.18.1).\n\n### Workarounds\n\nIf you cannot upgrade yet, consider applying the changes from PR [#4073](https://github.com/py-pdf/pypdf/pull/4073).","status":"published","published":"2026-10-01T16:44:33.58261Z","modified":"2026-10-01T17:45:17.628292762Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"}],"updated_at":"2026-11-02T15:52:57.671918Z"},{"id":"UBUNTU-CVE-2026-102997","description":"pypdf is a free and open-source pure-python PDF library. Prior to 6.18.1, a crafted PDF containing a partially malformed /FlateDecode stream with padded data can force pypdf/filters.py to use inefficient byte-by-byte decompression while the earlier recovery counter fails to advance for bytes that successfully decode, causing long runtimes and application unavailability. This is a residual issue after the malformed FlateDecode recovery fix. This issue is fixed in version 6.18.1.","status":"published","published":"2026-09-30T21:17:00Z","modified":"2026-10-17T12:57:57.341425782Z","cvss":[{"version":"4.0","score":8.7,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","level":"high"},{"version":"3.1","score":7.5,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","level":"high"}],"updated_at":"2026-11-02T16:55:58.519486Z"},{"id":"CLSA-2026-1791448168","title":"TuxCare security update for pypdf (6 CVEs)","description":"TuxCare rebuilt pypdf to address 6 CVEs. Fixed in 5.9.0.post19+tuxcare.","status":"published","published":"2026-10-08T08:29:28Z","modified":"2026-10-15T09:47:41.037195416Z","updated_at":"2026-11-02T15:43:49.016976Z"}]}}