Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
pypdf versions before 6.21.0 are vulnerable to excessive memory use when parsing PDF arrays and dictionaries containing many elements. An attacker who can get the library to process a specially crafted PDF can cause large memory consumption. Upgrade to pypdf 6.21.0 or later; the source does not describe any other workaround.
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 0.0040, the 34th percentile, on 5 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-f54x-cmq8-qg57
- OSV: GHSA-f54x-cmq8-qg57
- github.com/py-pdf/pypdf/security/advisories/GHSA-f54x-cmq8-qg57
- nvd.nist.gov/vuln/detail/CVE-2026-113790
- github.com/py-pdf/pypdf/pull/4218
- github.com/py-pdf/pypdf/commit/18bd2981a74479483a0b9507602c58a63d6c9b12
- github.com/py-pdf/pypdf
- github.com/py-pdf/pypdf/releases/tag/6.21.0