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Fencer Intel
high 7.2

CVE-2026-62971 json

OWASP CRS: XML Attribute Value Bypass

published 4mo ago modified 15h ago also GHSA-6jp8-c2w2-x7wr , EUVD-2026-123614

Unreviewed: the maintainers' own advisory

Published by the maintainers on their GitHub repository coreruleset/coreruleset. GitHub has not reviewed it into the GitHub Advisory Database, so the affected packages and versions are the maintainers' word. Read the full advisory on GitHub.

cvss
7.2
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
—
no EPSS score yet
public exploits
0
none known

Summary

The OWASP core rule set (CRS) is a set of generic attack detection rules for use with compatible web application firewalls. Prior to versions 3.3.10, 4.25.1, and 4.28.0, CRS rules in the 921 (protocol-attack), 930 (LFI), 931 (RFI), 932 (RCE), 933 (PHP), 934 (generic), 941 (XSS), 942 (SQLi), and 943 (session-fixation) families inspect XML request bodies via the XPath expression XML:/*. That expression matches only element text nodes — it does not match XML attribute values. As a result, an attacker who places an attack payload inside an XML attribute (e.g. <a href="javascript:alert(1)=window.name"></a> or <a value="' OR 1=1 --"></a>) bypasses CRS detection entirely. This is verified empirically against a local CRS test instance and against the public CRS sandbox. The bypass affects approximately 159 rules across 9 rule files and applies at every paranoia level (PL1 through PL4), since the variable list is more or less shared across PLs. The 944 (Java) family is the only one that correctly includes XML://@* in addition to XML:/* and is therefore unaffected. This issue has been patched in versions 3.3.10, 4.25.1, and 4.28.0.

Patch / fix

Is CVE-2026-62971 in your stack? 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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CVSS scores

assigned by version score vector
CNA 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:L/A:N

Affected products

  • coreruleset coreruleset

Classification

Weakness
  • CWE-138 Improper Neutralization of Special Elements

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 coreruleset/coreruleset published their own advisory on GitHub. Reviewed sources take precedence over it.