Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
pypdf versions before 6.18.1 are vulnerable to large memory consumption when parsing font data. An attacker can craft a PDF with unusually large values in the /Widths entry of TrueType or Type1 fonts, which is triggered during operations such as text extraction. Upgrade to pypdf 6.18.1 or later. The source gives no other workaround beyond applying the referenced upstream patch.
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 |
|---|---|---|---|---|
| 8.7 | High | 4.0 | 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 | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0034, the 27th percentile, on 8 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 30 Sept 2026, 21:17 UTC Confirmed by NVD
- 31 Oct 2026, 14:09 UTC First seen by agentprime
- 31 Oct 2026, 14:09 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-g9cg-prrw-2r8q
- OSV: GHSA-g9cg-prrw-2r8q
- github.com/py-pdf/pypdf/security/advisories/GHSA-g9cg-prrw-2r8q
- nvd.nist.gov/vuln/detail/CVE-2026-102996
- github.com/py-pdf/pypdf/pull/4072
- github.com/py-pdf/pypdf/commit/0fb26eb8cdd01c44b3b2c9fe8329751be2f7cfd5
- github.com/py-pdf/pypdf
- github.com/py-pdf/pypdf/releases/tag/6.18.1