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CVE-2026-77299VulnerabilityPublished Updated

Red Hat Security Advisory: Red Hat Hardened Images RPMs Security Update

Affects Red HatSource GCVE Database

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Authoritative record:CVE-2026-77299· High 7.5

Not known to be exploited · CVSS 7.5 High : upgrade Red Hat regexp2 to 2.3.0 soon.

Data as of 13 Nov 2026, 14:31 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.

Thin evidence

One scorer or none
CVSS scores by source
CNA (GitHub_M)CVSS 3.17.5
Patch
Available – fixed in 2.3.0
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 6 Nov 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.

What to do

Upgrade regexp2 and github.com/dlclark/regexp2 to 2.3.0.

Affected software

ProductAffectedFixed in
dlclarkregexp2Affected
  • <2.3.0
Fixed in
  • 2.3.0
Gogithub.com/dlclark/regexp2pkg:golang/github.com/dlclark/regexp2Other threatsAffected
  • <2.3.0
Fixed in
  • 2.3.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

Red Hat has released updated RPM packages (loki3.6-3.6.20-0.2.hum1) that include the fix for this vulnerability. Users should apply these updates to remediate the issue. Until patched, mitigations include restricting regular expression compilation to trusted inputs, validating and rejecting untrusted patterns with large quantifiers or zero-width repetitions, and enforcing resource limits such as RLIMIT_AS and cgroups memory limits to contain memory usage. Upgrading to regexp2 version 2.3.0 or later is recommended as it enforces backtracking stack size limits and optimizes pattern evaluation to prevent this issue. Red Hat notes that no fully effective mitigation exists other than applying the official patch.

Description

A denial of service vulnerability (CVE-2026-77299) exists in the regexp2 library used by Red Hat Hardened Images RPMs. The flaw allows a remote attacker to cause unbounded memory allocation by submitting a crafted regular expression with a large repetition quantifier on an empty subexpression. This leads to rapid memory exhaustion and application crash. The issue affects Go applications that compile or evaluate untrusted user-supplied regular expressions using regexp2. Deployments restricting pattern definitions to trusted inputs are not affected. Mitigations include restricting untrusted patterns, enforcing resource limits, and upgrading to patched versions when available.

References

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