CVE-2026-119205: pypdf has possible infinite loop when cloning dictionaries
Affects pypdfSource GCVE Database
Not known to be exploited · CVSS 7.1 High : upgrade to 6.21.4 soon.
Data as of 31 Oct 2026, 01:54 UTC
Thin evidence
One scorer or none| CNA (GitHub_M) | CVSS 4.0 | 7.1 |
|---|
- Patch
- Available – fixed in 6.21.4
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 29 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.
What to do
Upgrade pypdf to 6.21.4.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| PyPIpypdf | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade pypdf to version 6.21.4 or later, where the vulnerability is fixed. If immediate upgrade is not possible, apply the changes from pull request #4288 as a temporary workaround to prevent the infinite loop during dictionary cloning.
Description
A vulnerability in pypdf prior to version 6.21.4 allows an attacker to craft a malicious PDF that triggers an infinite loop when cloning a DictionaryObject. This flaw has been assigned CVE-2026-119205 and is rated high severity with a CVSS score of 7.1. The issue is fixed in pypdf version 6.21.4. Users unable to upgrade immediately can apply the changes from the referenced pull request as a workaround.
References
- github.com/py-pdf/pypdf/security/advisories/GHSA-mfr5-77xh-9j7h (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-119205 (opens in a new tab)
- github.com/py-pdf/pypdf/pull/4288 (opens in a new tab)
- github.com/py-pdf/pypdf/commit/f176db1a1f7f9af3e472e69a843ef1175653b044 (opens in a new tab)
- github.com/py-pdf/pypdf (opens in a new tab)
- github.com/py-pdf/pypdf/releases/tag/6.21.4 (opens in a new tab)