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Vulnerabilities

Vulnerability · CVE-2026-113791

pypdf: Possible large memory usage when parsing content streams

Published Oct 21, 2026 · catalog updated Oct 22, 2026 · pypdf: Possible large memory

Last checked Oct 28, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-113791. EPSS is 0.39%. Act only if a listed version of pypdf: Possible large memory 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: Possible large memory).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.0
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.39%
Remediation
Version ranges on file
Affected products
PyPI pypdf · pip pypdf · pypi pypdf · vendor py-pdf pypdf

### Impact An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing content streams with many small operations. ### Patches This has been fixed in [pypdf==6.21.0](https://github.com/py-pdf/pypdf/releases/tag/6.21.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#4218](https://github.com/py-pdf/pypdf/pull/4218).

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.

  • PyPI pypdf0 → 6.21.0
  • pip pypdf< 6.21.0
  • pypi pypdfversion unspecified
  • vendor py-pdf pypdfversion unspecified

How to fix CVE-2026-113791

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-2026-113791. EPSS is 0.39%. Act only if a listed version of pypdf: Possible large memory is installed.

Which versions are affected?

Compare what you have installed with 0 → 6.21.0, < 6.21.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-400: Uncontrolled Resource Consumption; CWE-770: Allocation of Resources Without Limits or Throttling. EPSS 0.39%. 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. Oct 22, 2026 · GitHub Advisory Database

    Detected

    ### Impact An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing content streams with many small operations. ### Patches This has been fixed in [pypdf==6.21.0](https://github.com/py-pdf/pypdf/releases/tag/6.21.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#4218](https://github.com/py-pdf/pypdf/pull/4

  2. Oct 22, 2026 · GitHub Advisory Database

    Updated

    ### Impact An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing content streams with many small operations. ### Patches This has been fixed in [pypdf==6.21.0](https://github.com/py-pdf/pypdf/releases/tag/6.21.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#4218](https://github.com/py-pdf/pypdf/pull/4

  3. Oct 22, 2026 · PyPA Advisory Database

    Fix available

    pypdf fixed in 6.21.0

  4. Oct 22, 2026 · PyPA Advisory Database

    Fix available

    pypdf fixed in 6.21.0

  5. Oct 22, 2026 · PyPA Advisory Database

    Updated

    ### Impact An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing content streams with many small operations. ### Patches This has been fixed in [pypdf==6.21.0](https://github.com/py-pdf/pypdf/releases/tag/6.21.0). ### Workarounds If you cannot upgrade yet, consider applying the changes from PR [#4218](https://github.com/py-pdf/pypdf/pull/4

Sources

  • CVE.orgVulnerability recordCVE-2026-113791

    pypdf is a free and open-source pure-python PDF library. Prior to 6.21.0, an attacker can craft a PDF containing a content stream with many small operations, causing parsing to consume large amounts of memory. This issue is fixed in version 6.21.0.

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-113791

    30-day exploitation probability 0.39%

    first.org
  • GitHub Advisory DatabasePackage advisoryGHSA-cgf9-327m-v77c

    pypdf: Possible large memory usage when parsing content streams

    github.com
  • GitLab Advisory DatabasePackage advisoryCVE-2026-113791

    An attacker who uses this vulnerability can craft a PDF which leads to large memory usage. This requires parsing content streams with many small operations.

    advisories.gitlab.com
  • PyPA Advisory DatabasePackage advisoryGHSA-cgf9-327m-v77c

    pypdf: Possible large memory usage when parsing content streams

    osv.dev

References

Freshness

Last verified in this catalog Oct 28, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 28, 2026
  • GitHub Advisory DatabaseOct 23, 2026
  • PyPA Advisory DatabaseOct 23, 2026
  • GitLab Advisory DatabaseOct 23, 2026
  • CVE.orgOct 23, 2026