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TI-2026-58861 Aliases CVE-2026-86000GHSA-gjv8-xp57-g29c

Soup Sieve: Polynomial-time ReDoS (O(n²)) in the `IDENTIFIER` / `VALUE` selector sub-patterns

Priority MEDIUM 63CWE-1333Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Denial of service
Confidentiality · integrity · availability
None · None · Low
Fix status
Partial Red Hat: 1 fixed, 11 without a fix

Attack profile from CVSS 3.1 · CNA. Fix status from CNA, GitHub and Red Hat. Impact type from CWE-1333.

Summary

Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.9, the selector parser in src/soupsieve/css_parser.py defines IDENTIFIER with adjacent quantified groups over overlapping character classes, and VALUE embeds IDENTIFIER for attribute selectors. When an attacker-controlled selector contains a long identifier or unquoted attribute-value run followed by input that makes the overall match fail, the regular expression engine explores quadratically many splits between the overlapping groups. User-controlled selectors can reach this path through soupsieve.compile(), soupsieve.select(), or BeautifulSoup.select(), while applications using only hard-coded selectors are unaffected. The resulting CPU consumption can hold the Python GIL, exhaust application workers, and stall a service; successful plain identifier matches are linear, and the issue does not cause memory corruption or code execution. The issue is fixed in version 2.9.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00609 49th percentileScored 2026-11-07
Fix Partial soupsieve (facelessuser): 2.9soupsieve (PyPI): 2.9.0Red Hat: 1 advisoryRed Hat: 1 fixed, 11 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
facelessusersoupsievebefore 2.92.9Patch availableCNA
—soupsieve (PyPI)before 2.9.02.9.0Patch availableGHSA-gjv8-xp57-g29c
  • soupsieve Vendorfacelessuser Affected before 2.9 Fixed in 2.9 Patch available CNA
  • soupsieve (PyPI) Vendor— Affected before 2.9.0 Fixed in 2.9.0 Patch available GHSA-gjv8-xp57-g29c

Remediation

  • Fix · CNA soupsieve (facelessuser) Fixed in 2.9
  • Fix · GHSA-gjv8-xp57-g29c soupsieve (PyPI) Fixed in 2.9.0 Advisory →

Red Hat 1 advisory

  • RHSA-2026:84734 Released 2026-10-19 · Red Hat rating Critical
    RHOAI 3.4.5 - Red Hat OpenShift AI
    • Red Hat OpenShift AI 3.4 registry.redhat.io/rhoai/odh-ai-gateway-payload-processing-rhel9, registry.redhat.io/rhoai/odh-automl-rhel9, registry.redhat.io/rhoai/odh-autorag-rhel9 +47

Vendor assessments

Red Hat

Red Hat rating: Moderate. Red Hat's page for this CVE →

ProductStatusPlan or fix
Exploit IntelligenceAffectedNo fix yet
Lightspeed CoreAffectedNo fix yet: Fix deferred
Migration Toolkit for Applications 8AffectedNo fix yet: Fix deferred
OpenShift LightspeedAffectedNo fix yet: Fix deferred
Red Hat Ansible Automation Platform 2AffectedNo fix yet: Fix deferred
Red Hat OpenShift AI (RHOAI)AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 5AffectedNo fix yet: Fix deferred
Red Hat OpenShift Virtualization 4AffectedNo fix yet: Fix deferred
Red Hat OpenStack Platform 17.1AffectedNo fix yet: Fix deferred
Red Hat Quay 3AffectedNo fix yet: Fix deferred
Red Hat OpenShift AI 3.4Fixed RHSA-2026:84734
Not affected: 2 products
  • Red Hat Hardened Images
  • Red Hat OpenShift AI 3.4

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-86000
  2. 2026-10-03 Alias added: GHSA-gjv8-xp57-g29c
  3. 2026-10-20 Fix available: RHSA-2026:84734 · Red Hat
  4. 2026-10-20 Fix available: Red Hat OpenShift AI 3.4 · Red Hat
  5. 2026-10-30 Affected versions changed · Red Hat

References

Advisory 1

Other 4

  • TI-2026-47703 pymdown-extensions: Exponential-backtracking ReDoS in caret, tilde, betterem, and magiclink inline processors CVSS 3.1HIGH 7.5
  • TI-2026-36631 Soup Sieve: Regular Expression Denial of Service (ReDoS) in soupsieve Selector Parser CVSS 3.1HIGH 7.5
  • TI-2026-36630 Soup Sieve: Memory Exhaustion via Large Comma-Separated Selector Lists in soupsieve CVSS 3.1HIGH 7.5
  • TI-2023-15603 Arbitrary file inclusion with the pymdowm-snippets extension CVSS 3.1HIGH 7.5
  • TI-2026-58860 Regular expression denial of service in facelessuser soupsieve CVSS 3.1MEDIUM 5.3
  • TI-2026-44140 PyMdown Extensions: Path traversal in the b64 extension lets <img src> read files outside base_path CVSS 3.1MEDIUM 5.3
See all 8 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences