🛡️ CVE-2025-13836 on Debian — pypy3

⚪ Unknown ✅ No Known Exploit OSV

N/A

CVSS Score

0 Low4 Medium7 High9 Critical10

Description

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.

Distribution advisory

This page covers CVE-2025-13836 as tracked by Debian, for the package pypy3. The fix is available in version 7.3.21+dfsg-1; earlier versions remain affected.

How this vulnerability can be exploited

This issue can be reached over the network, attack complexity is low, an attacker needs no privileges on the target. No user interaction is required. The scope is unchanged, so the impact stays within the vulnerable component. Rated impact: confidentiality none, integrity none, availability high.

Affected software

DEBIAN-CVE-2025-13836 is recorded against 5 packages.

pypy3 (fixed in 7.3.21+dfsg-1)
python3.11 (fixed in 3.11.2-6+deb12u7)
python3.13 (fixed in 3.13.11-1)
python3.14 (fixed in 3.14.2-1)
python3.9 (fixed in 3.9.2-1+deb11u4)

Timeline and source

Published on 1 December 2025 and last revised on 4 August 2026. No public exploit is currently recorded for this entry. Record sourced from OSV.

References

security-tracker.debian.org (Advisory)

CVE-2025-13836 on other distributions

Each distribution ships its own build and its own fixed version. Pick the one you run:

BellSoft Base record Debian 12 (Root.io)Debian 13 (Root.io)Ubuntu

Details

Severity Unknown

CVSS Score N/A

CVSS Vector CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE N/A

Public Exploit ✅ No

Source OSV

Published 2025-12-01

Updated 2026-08-20

Modified 2026-08-04

Fix URL N/A

Affected Packages

Software	From version	Fixed in
pypy3	—	7.3.21+dfsg-1
python3.11	—	3.11.2-6+deb12u7
python3.13	—	3.13.11-1
python3.14	—	3.14.2-1
python3.9	—	3.9.2-1+deb11u4

References

ADVISORY https://security-tracker.debian.org/tracker/CVE-2025-13836

🔗 NVD 🔗 Mitre

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