CVE-2026-112273: libtins through 4.6 Heap Out-of-Bounds Read via DNS::compose_name

Severity: medium (CVSS 5.3 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.6% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-10-19 · updated 2026-10-22
Weakness: CWE-125

Description

libtins through 4.6 contains a heap out-of-bounds read vulnerability in DNS::compose_name in src/dns.cpp that allows remote attackers to read past the packet buffer by sending a label ending exactly at the packet end. Attackers can deliver crafted DNS packets whose additional, answer, or authority records trigger a one-byte read when parsed, crashing applications on hardened allocators.

Affected products

libtins: through 4.6

References

https://github.com/mfontanini/libtins
https://github.com/mfontanini/libtins/blob/v4.6/src/dns.cpp#L338-L389
https://hackmd.io/@haindpwn/libtins-dns-name-parsing-oob-read
https://www.vulncheck.com/advisories/libtins-through-4.6-heap-out-of-bounds-read-via-dns-compose-name
https://hackmd.io/@haindpwn/cve-2026-112273-112274-libtins-dns-name-parsing-oob-read

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