6.3

CVE-2026-3276: Potential DoS via quadratic complexity in unicodedata.normalize()

Awaiting analysis
AliasesALPINE-CVE-2026-3276SUSE-SU-2026:3655-1UBUNTU-CVE-2026-3276
Published 03-06-2026Last modified 13-08-2026

Vulnerability summary

CVE-2026-3276 is a medium (CVSS 6.3) Inefficient Algorithmic Complexity vulnerability in python software foundation cpython. EPSS estimates a 0.49% chance of exploitation in the next 30 days, higher than 41.9% 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
6.3/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.49%
0%100%
Low · -0.23 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 36 · Related 32
OPENSUSE-SU-2026:11101-1OPENSUSE-SU-2026:11181-1OPENSUSE-SU-2026:11426-1OPENSUSE-SU-2026:11427-1OPENSUSE-SU-2026:11428-1OPENSUSE-SU-2026:11534-1

Timeline

  1. 03-06-2026
    PublishedVulnerability first disclosed.
  2. 13-08-2026
    Last modifiedVulnerability information updated.

Description

unicodedata.normalize() can take excessive CPU time when processing specially crafted Unicode input containing long runs of combining characters with alternating Canonical Combining Class values. This affects all normalization forms.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.49%

Chance of exploitation in the next 30 days

Percentile

42%

Versus all other CVEs

30-day change

Decrease -0.23 pp

From 0.71% 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.

Suse26 products
  • python311-core&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-ESPOS< 3.11.15-150400.9.97.1
  • python311-core&distro=SUSE Linux Enterprise High Performance Computing 15 SP4-LTSS< 3.11.15-150400.9.97.1
  • python311-core&distro=SUSE Linux Enterprise High Performance Computing 15 SP5-ESPOS< 3.11.15-150400.9.97.1
  • python311-core&distro=SUSE Linux Enterprise High Performance Computing 15 SP5-LTSS< 3.11.15-150400.9.97.1
  • python311-core&distro=SUSE Linux Enterprise Module for Public Cloud 15 SP4< 3.11.15-150400.9.97.1
Ubuntu13 products
  • pypy3All versions (No fix recorded)
  • python2.7All versions (No fix recorded)
  • python3.10< 3.10.12-1~22.04.16
  • python3.11All versions (No fix recorded)
  • python3.12< 3.12.3-1ubuntu0.15
Chainguard5 products
  • python-3.10< 3.10.20-r8
  • python-3.11< 3.11.15-r6
  • python-3.12< 3.12.13-r8
  • python-3.13< 3.13.14-r0
  • python-3.14< 3.14.6-r0
Wolfi5 products
  • python-3.10< 3.10.20-r8
  • python-3.11< 3.11.15-r6
  • python-3.12< 3.12.13-r8
  • python-3.13< 3.13.14-r0
  • python-3.14< 3.14.6-r0
Debian3 products
  • python3.11< 3.11.2-6+deb12u9
  • python3.13< 3.13.14-1 | < 3.13.5-2+deb13u3
  • python3.14< 3.14.6-1
Alpine1 product
  • python3< 3.14.7-r0
Python software foundation1 product
  • cpython< 3.10.21 | ≥ 3.11.0, < 3.11.16 | ≥ 3.12.0, < 3.12.14 | ≥ 3.13.0, < 3.13.14 | ≥ 3.14.0, < 3.14.6 | ≥ 3.15.0a1, < 3.15.0b2

7 vendors · 54 products

References

24 links
Show all 24 references