Amazon Linux 2 (EOS) Security Advisory: ALAS2-2026-3876
Advisory Released Date: 2026-08-31
Advisory Updated Date: 2026-08-31
A vulnerability was found in libsoup's WebSocket frame parsing implementation. The library fails to validate length rules specified in RFC 6455 SS5.5, which mandates that all WebSocket control frames (e.g., PING, PONG, CLOSE) contain a payload of 125 bytes or less. A remote, unauthenticated attacker can exploit this by sending a non-compliant, oversized control frame. Because the parser handles this protocol violation improperly instead of throwing an immediate connection termination error, it triggers a internal processing crash, resulting in a remote denial of service (DoS) for applications utilizing libsoup WebSockets. (CVE-2026-15711)
Affected Packages:
libsoup
Note:
This advisory is applicable to Amazon Linux 2 (AL2) Core repository. Visit this FAQ section for the difference between AL2 Core and AL2 Extras advisories.
Issue Correction:
Run yum update libsoup or yum update --advisory ALAS2-2026-3876 to update your system.
aarch64:
libsoup-2.56.0-6.amzn2.0.8.aarch64
libsoup-devel-2.56.0-6.amzn2.0.8.aarch64
libsoup-debuginfo-2.56.0-6.amzn2.0.8.aarch64
i686:
libsoup-2.56.0-6.amzn2.0.8.i686
libsoup-devel-2.56.0-6.amzn2.0.8.i686
libsoup-debuginfo-2.56.0-6.amzn2.0.8.i686
src:
libsoup-2.56.0-6.amzn2.0.8.src
x86_64:
libsoup-2.56.0-6.amzn2.0.8.x86_64
libsoup-devel-2.56.0-6.amzn2.0.8.x86_64
libsoup-debuginfo-2.56.0-6.amzn2.0.8.x86_64