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Fencer Intel
high 7.5

CVE-2026-49477 json

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

published 5mo ago modified 18d ago also EUVD-2026-44538 , GHSA-836r-79rf-4m37 , PYSEC-2026-3072

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

Is CVE-2026-49477 in your dependencies? Fencer shows which of your repositories are affected as soon as an advisory lands, and opens the fix as a pull request.

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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
3mo ago

Exploit prediction

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

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
GitHub 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

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 Intel 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.

The maintainers of facelessuser/soupsieve published their own advisory on GitHub. Reviewed sources take precedence over it.