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Vulnerabilities

Vulnerability · CVE-2026-22691

pypdf is a free and open-source pure-python PDF library.

Published Jan 10, 2026 · catalog updated Nov 2, 2026 · pypdf is a free

Last checked Nov 6, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-22691. EPSS is 0.43%. Act only if a listed version of pypdf is a free is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (pypdf is a free).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Low2.7
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.43%
Remediation
Version ranges on file
Affected products
cpe py-pdf/pypdf · vendor py-pdf pypdf < 6.6.0

pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading mode is affected. Only the non-strict reading mode is affected. This issue has been patched in version 6.6.0.

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • cpe py-pdf/pypdf< 6.6.0
  • vendor py-pdf pypdf < 6.6.0< 6.6.0

How to fix CVE-2026-22691

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-22691. EPSS is 0.43%. Act only if a listed version of pypdf is a free is installed.

Which versions are affected?

Compare what you have installed with py-pdf pypdf < 6.6.0 < 6.6.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-1333: Inefficient Regular Expression Complexity; CWE-400: Uncontrolled Resource Consumption. EPSS 0.43%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Jan 10, 2026 · EUVD

    Detected

    pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading

  2. Jan 12, 2026 · EUVD

    Updated

    pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading

  3. Nov 2, 2026 · NIST NVD

    Updated

    pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding the cross-reference table, PDF files with lots of whitespace characters become problematic. Only the non-strict reading

Sources

  • CVE.orgVulnerability recordCVE-2026-22691

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-22691

    30-day exploitation probability 0.43%

    first.org
  • EUVDVulnerability recordEUVD-2026-1691

    pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding

    euvd.enisa.europa.eu
  • NIST NVDVulnerability recordCVE-2026-22691

    pypdf is a free and open-source pure-python PDF library. Prior to version 6.6.0, pypdf has possible long runtimes for malformed startxref. An attacker who uses this vulnerability can craft a PDF which leads to possibly long runtimes for invalid startxref entries. When rebuilding

    nvd.nist.gov

References

Freshness

Last verified in this catalog Nov 6, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 6, 2026
  • NIST NVDNov 2, 2026
  • CVE.orgOct 31, 2026
  • EUVDOct 30, 2026