CVE-2025-57809High· 7.5▾ TwilightA flaw was found in xgrammar. Recursive grammar definitions could trigger infinite recursion during parsing in GrammarMatcherBase::ExpandEquivalentStackElements, leading to unbounded stack growth and a segmentation fault. This vulnerabilit…
▾ Twilight zone — High severity, or a signal on a lesser flaw
impact 41.3 · likelihood 0.1 · exploitation 0
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Exploit-prediction probability, daily snapshots since Jul 31.
Disclosure to exploitation, from the record and what we observed since indexing it.
Disclosed via CSAF
0.5%
Last analysed / modified upstream
0.5% → 0.5%
A flaw was found in xgrammar. Recursive grammar definitions could trigger infinite recursion during parsing in GrammarMatcherBase::ExpandEquivalentStackElements, leading to unbounded stack growth and a segmentation fault. This vulnerability allows remote attackers to cause a denial of service (DoS) when untrusted grammar is processed.
xgrammar: XGrammar affected by Denial of Service by infinite recursion grammars — rated Important by Red Hat. Released 2025-08-25, updated 2026-09-21.
Affected:
Fixed:
No fix planned:
For more information visit https://access.redhat.com/errata/RHSA-2025:19427 https://access.redhat.com/errata/RHSA-2025:19427 For more information visit https://access.redhat.com/errata/RHSA-2025:19429 https://access.redhat.com/errata/RHSA-2025:19429 For more information visit https://access.redhat.com/errata/RHSA-2025:19424 https://access.redhat.com/errata/RHSA-2025:19424
Workarounds / mitigations:
Affected packages:
xgrammar < 0.1.21Patched in:
xgrammar 0.1.21Connected by shared product, vendor, weakness, or advisory.
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