Amazon Linux 2027 Preview Security Advisory: ALAS2027-2026-090
Advisory Release Date: 2026-09-28 09:00 Pacific
Advisory Updated Date: 2026-09-28 09:00 Pacific
Severity:
Important
Issue Overview:
A use-after-free / double-free in c-ares' query-completion handling. The
same flaw -- a query's callback being invoked while the query is still
linked in the channel's internal lookup structures -- is present at
multiple points in the resend/finish path (timeout handling, response
handling, and query dispatch). If the query, or for `ares_getaddrinfo()`
the owning `host_query`, is freed as a side effect of that callback, it
is then accessed and/or freed a second time. (CVE-2026-33630)
CPU-exhaustion denial of service via unbounded DNS name compression pointer chains (CVE-2026-69184)
Affected Packages:
c-ares
Issue Correction:
Run yum update c-ares to update your system.
New Packages:
aarch64:
c-ares-1.34.8-1.amzn2027.0.1.aarch64
c-ares-debugsource-1.34.8-1.amzn2027.0.1.aarch64
c-ares-debuginfo-1.34.8-1.amzn2027.0.1.aarch64
c-ares-devel-1.34.8-1.amzn2027.0.1.aarch64
src:
c-ares-1.34.8-1.amzn2027.0.1.src
x86_64:
c-ares-debuginfo-1.34.8-1.amzn2027.0.1.x86_64
c-ares-devel-1.34.8-1.amzn2027.0.1.x86_64
c-ares-debugsource-1.34.8-1.amzn2027.0.1.x86_64
c-ares-1.34.8-1.amzn2027.0.1.x86_64