Machine-written summary
Summary written by Claude Haiku from the source advisory. Not reviewed by a person.
Pillow versions before 13.0.0 have a flaw in TarIO, the helper class that reads a member from a tar archive. It does not check that a tar header's size field is non-negative, so a crafted header with a negative size makes the reader seek back to where it started and loop forever. An attacker who can get a crafted tar file passed to PIL.TarIO.TarIO can hang the process at full CPU; the source reports no confidentiality or integrity impact. The fix is to upgrade to Pillow 13.0.0 or later.
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 |
|---|---|---|---|---|
| 7.1 | High | 4.0 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N | CNA (GitHub_M) |
- CISA KEV Not listed.
- EPSS 0.0034, the 28th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.
Timeline
- 31 Oct 2026, 14:07 UTC First seen by agentprime
- 31 Oct 2026, 14:07 UTC Confirmed by OSV
Sources
- GitHub Advisory Database: GHSA-3j72-p6qg-6xp7
- OSV: GHSA-3j72-p6qg-6xp7
- github.com/python-pillow/Pillow/security/advisories/GHSA-3j72-p6qg-6xp7
- nvd.nist.gov/vuln/detail/CVE-2026-96642
- github.com/python-pillow/Pillow/pull/10012
- github.com/python-pillow/Pillow/commit/19b695fdcc5eddc37374e2b1645fc4185edaf71d
- github.com/python-pillow/Pillow
- github.com/python-pillow/Pillow/releases/tag/13.0.0