CVE-2026-5172
CVE-2026-5172 is a high-severity vulnerability with a CVSS 3.x base score of 7.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-125.
Key facts
- Severity: High (CVSS 3.x base score 7.3)
- EPSS exploit prediction: 1% (56th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-29156
- Weakness: CWE-125
- Published:
- Last modified:
Description
A buffer overflow in dnsmasq’s extract_addresses() function allows an attacker to trigger a heap out-of-bounds read and crash by exploiting a malformed DNS response, enabling extract_name() to advance the pointer past the record’s end.
Frequently asked questions
- What is CVE-2026-5172?
- A buffer overflow in dnsmasq’s extract_addresses() function allows an attacker to trigger a heap out-of-bounds read and crash by exploiting a malformed DNS response, enabling extract_name() to advance the pointer past the record’s end.
- How severe is CVE-2026-5172?
- CVE-2026-5172 has a CVSS 3.x base score of 7.3, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is low, integrity low, and availability low.
- Is CVE-2026-5172 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (56th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-5172?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-5172 have an EU (EUVD) identifier?
- Yes. CVE-2026-5172 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-29156.
- When was CVE-2026-5172 published?
- CVE-2026-5172 was published on 2026-05-11 and last updated on 2026-06-30.
References
- https://github.com/NixOS/nixpkgs/pull/519082
- https://github.com/NixOS/nixpkgs/pull/519093
- https://github.com/pi-hole/FTL/releases/tag/v6.6.2
- https://lists.thekelleys.org.uk/pipermail/dnsmasq-discuss/2026q2/018471.html
- https://thekelleys.org.uk/dnsmasq/CVE/
- https://www.kb.cert.org/vuls/id/471747
- https://access.redhat.com/errata/RHSA-2026:19158
- https://access.redhat.com/security/cve/CVE-2026-5172
- https://bugzilla.redhat.com/show_bug.cgi?id=2458521
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-5172.json
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