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Fencer Vulns
high 7.5

CVE-2026-49477 json

Soup Sieve: Regular Expression Denial of Service (ReDoS) in soupsieve Selector Parser

published 2026-07-09 4 mo ago modified 2026-10-24 15 d ago also GHSA-836r-79rf-4m37 , PYSEC-2026-3072 , EUVD-2026-44538

cvss
7.5
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 51%
public exploits
0
none known

Summary

Soup Sieve is a CSS selector library designed to be used with Beautiful Soup 4. Prior to 2.8.4, the CSS selector parser in soupsieve contains a regular expression vulnerable to catastrophic backtracking when processing an attribute selector with an unterminated quoted value in soupsieve/css_parser.py, allowing an attacker who can supply untrusted CSS selector strings to soupsieve.compile() or Beautiful Soup .select() / .select_one() to cause CPU exhaustion and denial of service. This issue is fixed in version 2.8.4.

Patch / fix

  • pypi soupsieve 2.8.4
  • facelessuser soup_sieve 2.8.4
  • soupsieve Debian 14 2.8.4-1

debian advisories DEBIAN-CVE-2026-49477

  • python-rpds-py hummingbird 1 2026.6.3-1.hum1
  • python3-rpds-py hummingbird 1 2026.6.3-1.hum1

red hat advisories RHSA-2026:34119

  • python-soupsieve SLES for SAP 15 SP6, SLES 15 SP6-LTSS, SLE Module for Python 3 15 SP7 2.5-150600.3.3.1
  • python-soupsieve SLES for SAP 15 SP6, SLES for SAP 15 SP5, SLES for SAP 15 SP4 +8 more 1.9.5-150200.3.3.1
  • python-soupsieve SLES for SAP applications 16.0, SLES 16.0 2.6-160000.4.1

suse advisories SUSE-SU-2026:3240-1SUSE-SU-2026:3239-1SUSE-SU-2026:22660-1

  • python-soupsieve openSUSE Leap 16.0 2.6-160000.4.1

opensuse advisories openSUSE-SU-2026:21342-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-49477 updated cvss 7.5

soupsieve: Soupsieve: Denial of Service via crafted CSS selector strings

  • Red Hat Exploit Intelligence exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 Red Hat Lightspeed Core lightspeed-core/rag-tool-cuda-12.9-rhel9
    affected: no fix available
  • Red Hat Ansible Automation Platform 2 ansible-automation-platform-25/lightspeed-chatbot-rhel8
    affected: no fix planned “Will not fix”
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-workbench-jupyter-pytorch-llmcompressor-cuda-py312-rhel9 Red Hat OpenShift Container Platform 4 openshift4/ose-olm-catalogd-rhel9 Red Hat OpenShift Virtualization 4 container-native-virtualization/ocp-virt-validation-checkup-rhel9
    affected: no fix available
  • Red Hat Hardened Images python-rpds-py 2026.6.3-1.hum1, python3-rpds-py 2026.6.3-1.hum1
    fixed: vendor fix RHSA-2026:34119
  • Red Hat OpenShift AI 3.4 rhoai/odh-th06-cpu-torch210-py312-rhel9 1787076778, rhoai/odh-th06-rocm64-torch291-py312-rhel9 1787076481, rhoai/odh-th06-cuda130-torch210-py312-rhel9 1787077779, rhoai/odh-pipeline-runtime-minimal-cpu-py312-rhel9 1787073936, rhoai/odh-pipeline-runtime-pytorch-cuda-py312-rhel9 1787073873, rhoai/odh-pipeline-runtime-pytorch-rocm-py312-rhel9 1787073611, +13 more
    fixed: vendor fix RHSA-2026:60520
  • Red Hat Quay 3.9 quay/quay-rhel8 1788595574
    fixed: vendor fix RHSA-2026:65514
  • Red Hat Quay 3.10 quay/quay-rhel8 1788561841
    fixed: vendor fix RHSA-2026:66084
  • Red Hat Quay 3.12 quay/quay-rhel8 1788594376
    fixed: vendor fix RHSA-2026:66523
show 10 more
  • Red Hat Quay 3.14 quay/quay-rhel8 1788593843
    fixed: vendor fix RHSA-2026:70267
  • Red Hat Quay 3.15 quay/quay-rhel8 1788191755
    fixed: vendor fix RHSA-2026:63307
  • Red Hat Quay 3.16 quay/quay-rhel9 1789563753
    fixed: vendor fix RHSA-2026:69255
  • Red Hat Quay 3.17 quay/quay-rhel9 1790690298
    fixed: vendor fix RHSA-2026:74511
  • Red Hat Quay 3.18 quay/quay-rhel9 1791265590
    fixed: vendor fix RHSA-2026:81110
  • Red Hat Lightspeed Core lightspeed-core/rag-tool-cpu-rhel9 Red Hat Migration Toolkit for Applications 8 mta/mta-solution-server-rhel9
    not affected: vulnerable code not present
  • Red Hat OpenShift Lightspeed openshift-lightspeed/lightspeed-ocp-rag-rhel9, openshift-lightspeed-tech-preview/lightspeed-rag-tool-rhel9
    not affected: vulnerable code not in execute path
  • Red Hat Hardened Images python-attrs, python-urllib3
    not affected: component not present
  • Red Hat OpenShift AI (RHOAI) rhoai/odh-automl-rhel9, rhoai/odh-autorag-rhel9, rhoai/odh-th06-cpu-torch291-py312-rhel9, rhoai/odh-th06-cuda130-torch291-py312-rhel9, rhoai/odh-trustyai-nemo-guardrails-server-rhel9
    not affected: vulnerable code not in execute path
  • Red Hat OpenShift AI 3.4 rhoai/odh-cli-rhel9 1787330837, rhoai/rhai-cli-rhel9 1787330837, rhoai/odh-automl-rhel9 1786612415, rhoai/odh-mlflow-rhel9 1787226790, rhoai/odh-autorag-rhel9 1786612637, rhoai/odh-trainer-rhel9 1787089049, +81 more Red Hat Quay 3.9 quay/clair-rhel8 1788595308, quay/quay-builder-rhel8 1788595236, quay/quay-operator-rhel8 1788597635, quay/quay-operator-bundle 1788672362, quay/quay-bridge-operator-rhel8 1788596260, quay/quay-bridge-operator-bundle 1788597015, +3 more Red Hat Quay 3.10 quay/clair-rhel8 1787980047, quay/quay-builder-rhel8 1787980066, quay/quay-operator-rhel8 1787980042, quay/quay-operator-bundle 1788655774, quay/quay-bridge-operator-rhel8 1787980033, quay/quay-bridge-operator-bundle 1787981429, +3 more Red Hat Quay 3.12 quay/clair-rhel8 1788594175, quay/quay-builder-rhel8 1788594175, quay/quay-operator-rhel8 1788595337, quay/quay-operator-bundle 1788598412, quay/quay-bridge-operator-rhel8 1788594065, quay/quay-bridge-operator-bundle 1788595245, +3 more Red Hat Quay 3.14 quay/clair-rhel8 1788593782, quay/quay-builder-rhel8 1788593707, quay/quay-operator-rhel8 1788593658, quay/quay-operator-bundle 1788598271, quay/quay-bridge-operator-rhel8 1788594258, quay/quay-bridge-operator-bundle 1788595604, +3 more Red Hat Quay 3.15 quay/clair-rhel8 1787986213, quay/quay-builder-rhel8 1787824210, quay/quay-operator-rhel8 1787987657, quay/quay-operator-bundle 1788196149, quay/quay-bridge-operator-rhel8 1787986808, quay/quay-bridge-operator-bundle 1787987365, +3 more
    +3 more products
    Red Hat Quay 3.16 quay/clair-rhel9 1789191202, quay/quay-builder-rhel9 1789492236, quay/quay-operator-rhel9 1789190909, quay/quay-operator-bundle 1789627085, quay/quay-bridge-operator-rhel9 1789191073, quay/quay-bridge-operator-bundle 1789191920, +3 more Red Hat Quay 3.17 quay/clair-rhel9 1790689867, quay/quay-builder-rhel9 1790484991, quay/quay-operator-rhel9 1790689856, quay/quay-operator-bundle 1790696576, quay/quay-bridge-operator-rhel9 1790403610, quay/quay-bridge-operator-bundle 1790404339, +3 more Red Hat Quay 3.18 quay/clair-rhel9 1791279250, quay/quay-builder-rhel9 1791305715, quay/quay-rhel9-operator 1791305677, quay/quay-operator-bundle 1791306533, quay/quay-bridge-rhel9-operator 1791279118, quay/quay-bridge-operator-bundle 1791298533, +3 more
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
Proof of concept is public
Automatable
yes
Technical impact
partial
Assessed
3 mo ago

Exploit prediction

0.64% chance of exploitation in the next 30 days, higher than 51% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/facelessuser/soupsieve/security/advisories/GHSA-836r-79rf-4m37 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
OSV 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
GitHub 3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected packages

ecosystem package affected fixed in
pypi soupsieve
<2.8.4
2.8.4

Affected products

  • facelessuser soupsieve

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption
  • CWE-1333 Inefficient Regular Expression Complexity

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.