7.5

CVE-2025-13836: Excessive read buffering DoS in http.client

Analyzed
AliasesRHSA-2026:2419RHSA-2026:3897RHSA-2026:3900
Published 01-12-2025Last modified 03-03-2026

Vulnerability summary

CVE-2025-13836 is a high (CVSS 7.5) Uncontrolled Resource Consumption vulnerability in python software foundation cpython. EPSS estimates a 1.75% chance of exploitation in the next 30 days, higher than 77.8% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
1.75%
0%100%
Low · +0.12 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 60 · Related 46
DLA-4445-1MGASA-2025-0324OPENSUSE-SU-2025:15839-1OPENSUSE-SU-2025:15840-1OPENSUSE-SU-2025:15846-1OPENSUSE-SU-2025:15849-1

Timeline

  1. 01-12-2025
    PublishedVulnerability first disclosed.
  2. 03-03-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

9 scores · 7 sources · 2 versions

EPSS trend

Probability

1.75%

Chance of exploitation in the next 30 days

Percentile

78%

Versus all other CVEs

30-day change

Increase +0.12 pp

From 1.63% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Redhat10 products
  • python3.12< 0:3.12.1-4.el9_4.10 | < 0:3.12.9-1.el9_6.5 | < 0:3.12.12-2.el8_10
  • python3.12-debug< 0:3.12.1-4.el9_4.10 | < 0:3.12.9-1.el9_6.5 | < 0:3.12.12-2.el8_10
  • python3.12-debuginfo< 0:3.12.1-4.el9_4.10 | < 0:3.12.9-1.el9_6.5 | < 0:3.12.12-2.el8_10
  • python3.12-debugsource< 0:3.12.1-4.el9_4.10 | < 0:3.12.9-1.el9_6.5 | < 0:3.12.12-2.el8_10
  • python3.12-devel< 0:3.12.1-4.el9_4.10 | < 0:3.12.9-1.el9_6.5 | < 0:3.12.12-2.el8_10
Ubuntu7 products
  • python3.10< 3.10.12-1~22.04.13
  • python3.11< 3.11.0~rc1-1~22.04.1~esm7
  • python3.12< 3.12.3-1ubuntu0.10
  • python3.13< 3.13.7-1ubuntu0.2
  • python3.14< 3.14.0-1ubuntu0.1
Chainguard5 products
  • python-3.10< 3.10.19-r4
  • python-3.11< 3.11.14-r5
  • python-3.12< 3.12.12-r4
  • python-3.13< 3.13.11-r2
  • python-3.9All versions (No fix recorded)
Debian4 products
  • pypy3All versions (No fix recorded) | < 7.3.21+dfsg-1
  • python3.11< 3.11.2-6+deb12u7
  • python3.13< 3.13.11-1 | < 3.13.5-2+deb13u1
  • python3.14< 3.14.2-1
Wolfi4 products
  • python-3.10< 3.10.19-r4
  • python-3.11< 3.11.14-r5
  • python-3.12< 3.12.12-r4
  • python-3.13< 3.13.11-r2
Python1 product
  • python< 3.10.20 | ≥ 3.11.0, < 3.11.15 | ≥ 3.12.0, < 3.12.13 | ≥ 3.13.0, < 3.13.11 | 3.14.0 | 3.15.0:alpha1 | 3.15.0:alpha2
Python software foundation1 product
  • cpython< 3.10.20 | ≥ 3.11.0, < 3.11.15 | ≥ 3.12.0, < 3.12.13 | ≥ 3.13.0, < 3.13.11 | ≥ 3.14.0, < 3.14.1 | ≥ 3.15.0a1, < 3.15.0a3

7 vendors · 32 products

References

25 links
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