Vulnerability GHSA-jw7q-gvrg-4vj3
High Risk
HIGH RISK
CVSS Score: 8.0
Score Range: 7.0–8.9
High severity vulnerabilities (CVSS 7.0–8.9). Serious vulnerabilities that should be prioritized soon after critical fixes.
3 hours ago
October 01, 2026 at 03:06 PM UTC
pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)
1.0 - 6.18.0
1.0 - 6.18.0
Summary
pypdf: Possible long runtimes for partially malformed FlateDecode streams (Follow-up)
Details
Impact
An 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.
Patches
This has been fixed in pypdf==6.18.1.
Workarounds
If you cannot upgrade yet, consider applying the changes from PR #4073.
Related Vulnerabilities
Other vulnerabilities affecting the same packages
High Risk
3 hours ago
pypdf: Possible long runtimes with large amount of embedded files
1.0 - 6.18.1 GHSA-v247-6f48-mgcj
1.0 - 6.18.1 GHSA-v247-6f48-mgcj
High Risk
3 hours ago
pypdf: Possible long runtimes when generating appearance streams
1.0 - 6.18.1 GHSA-php9-fj8v-98fj
1.0 - 6.18.1 GHSA-php9-fj8v-98fj
High Risk
3 hours ago
pypdf: Possible large memory usage when retrieving alphabetical page labels
1.0 - 6.18.1 GHSA-w23x-9jrw-r45c
1.0 - 6.18.1 GHSA-w23x-9jrw-r45c
High Risk
3 hours ago
pypdf: Possible large memory usage when parsing font data
1.0 - 6.18.0 GHSA-g9cg-prrw-2r8q
1.0 - 6.18.0 GHSA-g9cg-prrw-2r8q
High Risk
3 hours ago
pypdf: Possible large memory usage for large /ToUnicode streams (Follow-up 2)
1.0 - 6.18.0 GHSA-fp3h-c4fm-7vvf
1.0 - 6.18.0 GHSA-fp3h-c4fm-7vvf
Impacted packages
Timeline
Published
3 hours ago
October 01, 2026 at 03:06 PM UTC
Fixed (6.18.1)
20 days ago
September 11, 2026 at 10:10 AM UTC
Last Modified
1 hour ago
October 01, 2026 at 05:56 PM UTC