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Vulnerabilities

Vulnerability · CVE-2025-13836

When reading an HTTP response from a server, if no read amount is specified, the default behavior will be to use Content-Length.

Published Dec 1, 2025 · catalog updated Mar 3, 2026 · Python Software Foundation CPython

Last checked Oct 27, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2025-13836. EPSS is 1.63%. Act only if a listed version of Python Software Foundation CPython is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.

Same product and reporting

Severity
Medium6.3
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
1.63%
Remediation
Version ranges on file
Affected products
vendor Python Software Foundation CPython 3.12.0 <3.12.13

When reading an HTTP response from a server, if no read amount is specified, the default behavior will be to use Content-Length. This allows a malicious server to cause the client to read large amounts of data into memory, potentially causing OOM or other DoS.

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.

  • vendor Python Software Foundation CPython 3.12.0 <3.12.133.12.0 <3.12.13

How to fix CVE-2025-13836

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-2025-13836. EPSS is 1.63%. Act only if a listed version of Python Software Foundation CPython is installed.

Which versions are affected?

Compare what you have installed with Python Software Foundation CPython 3.12.0 <3.12.13 3.12.0 <3.12.13. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 1.63%. 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. Dec 1, 2025 · EUVD

    Detected

    When reading an HTTP response from a server, if no read amount is specified, the default behavior will be to use Content-Length. This allows a malicious server to cause the client to read large amounts of data into memory, potentially causing OOM or other DoS.

  2. Mar 3, 2026 · EUVD

    Updated

    When reading an HTTP response from a server, if no read amount is specified, the default behavior will be to use Content-Length. This allows a malicious server to cause the client to read large amounts of data into memory, potentially causing OOM or other DoS.

Sources

  • CVE.orgVulnerability recordCVE-2025-13836

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2025-13836

    30-day exploitation probability 1.63%

    first.org
  • EUVDVulnerability recordEUVD-2025-200070

    When reading an HTTP response from a server, if no read amount is specified, the default behavior will be to use Content-Length. This allows a malicious server to cause the client to read large amounts of data into memory, potentially causing OOM or other DoS.

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 27, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • CVE.orgOct 27, 2026
  • FIRST EPSSOct 27, 2026
  • EUVDOct 26, 2026