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VulnerabilityPublished

CVE-2026-119205: pypdf has possible infinite loop when cloning dictionaries

Affects pypdfSource GCVE Database

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Authoritative record:CVE-2026-119205· High 7.1

Not known to be exploited · CVSS 7.1 High : upgrade to 6.21.4 soon.

Data as of 31 Oct 2026, 01:54 UTC

CVSS 4.0 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 4.07.1
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:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 29 Oct 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

ProductAffectedFixed in
PyPIpypdfAffected
  • <6.21.4
Fixed in
  • 6.21.4

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

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