Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
pypdf versions before 6.20.0 are vulnerable to excessive memory consumption when processing a PDF stream that has a large number of filters, or multiple filters that pass large amounts of data. An attacker who can supply a crafted PDF for the library to read can cause high memory use. Upgrade to pypdf 6.20.0 or later. The source gives no workaround beyond applying an unreleased code change, so upgrading is the fix.
Not analysed yet
We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.
Severity and exploitation
| Score | Rating | CVSS | Vector | Source |
|---|---|---|---|---|
| 6.0 | Medium | 4.0 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0035, the 29th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 21 Oct 2026, 16:17 UTC Confirmed by NVD
- 31 Oct 2026, 14:08 UTC First seen by agentprime
- 31 Oct 2026, 14:08 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-7mh2-4gg2-979f
- OSV: GHSA-7mh2-4gg2-979f
- github.com/py-pdf/pypdf/security/advisories/GHSA-7mh2-4gg2-979f
- github.com/py-pdf/pypdf/pull/4173
- github.com/py-pdf/pypdf/commit/80a84d4be6022d910874ccb0d2365400f3f0e185
- github.com/py-pdf/pypdf
- github.com/py-pdf/pypdf/releases/tag/6.20.0