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HIGH

CVE-2026-49477

CVSS v3

7.5

HIGH

EPSS Score

0.6 %

exploit probability, as of 2026-10-17

CISA KEV

No

known exploited

Exploitation

—

SSVC status

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Affected and fixed versions

Packages from OSV.dev and products from the vendors' CSAF advisories.

version not verifiedVersions not verified: read as OSV.dev and the vendors publish them, not checked against each vendor's release list.

Packages

  • soupsievePyPIall versions · fixed in 2.8.4

Vendor advisories

  • CVE-2026-49477 Red Hat Product Security71 products fixed · 7 known affected

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

    exploit-intelligence-tech-preview/vulnerability-analysis-rhel9 as a component of Exploit Intelligence · lightspeed-core/rag-tool-cuda-12.9-rhel9 as a component of Lightspeed Core · mta/mta-solution-server-rhel9 as a component of Migration Toolkit for Applications 8

  • RHSA-2026:81110 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Quay

  • RHSA-2026:74511 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Quay 3.17.5

  • RHSA-2026:70267 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Quay 3.14.9

  • RHSA-2026:69255 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Quay 3.16.6

  • RHSA-2026:66523 Red Hat Product Security4 products fixed

    Red Hat Security Advisory: Red Hat Quay 3.12.22

5 more advisories

Full record on NVD

Description

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.

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published
2026-07-14
Last Modified
2026-07-15

Frequently asked questions

What is CVE-2026-49477?

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.

Is CVE-2026-49477 actively exploited?

Active exploitation of CVE-2026-49477 has not been confirmed. Its EPSS score was 0.6% on 2026-10-17, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2026-49477?

CVE-2026-49477 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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