Amazon Linux 2 (EOS) Security Advisory: ALAS2-2026-3998
Advisory Released Date: 2026-10-12
Advisory Updated Date: 2026-10-12
FAQs regarding Amazon Linux ALAS/CVE Severity
A flaw was found in libsoup. When reassembling fragmented WebSocket messages into a GByteArray, libsoup did not adequately cap total message size against the limits of the underlying buffer type. A remote peer could send fragments that caused size truncation while the implementation still used the full length, leading to heap corruption or a crash. (CVE-2026-102557)
A flaw was found in libsoup. When max-incoming-payload-size is unlimited (0), SoupWebsocketConnection could grow its incoming GByteArray based on an attacker-controlled frame length until the length wrapped, causing a heap buffer overflow while reading frame data. (CVE-2026-102558)
A flaw was found in libsoup. When constructing a masked WebSocket client frame for a very large outgoing payload, size values passed to GByteArray allocation APIs could be truncated while the masking routine still used the full length, causing a heap buffer overflow. (CVE-2026-102559)
A flaw was found in SoupServer (libsoup). When an HTTP/1.x client sends a request with Expect: 100-continue and a request body, and SoupServer returns an early final (non-1xx) response before the body is read, the server neither drains the declared body bytes nor closes the connection. On a keep-alive connection, those leftover bytes are interpreted as a subsequent HTTP request. A remote, unauthenticated attacker can place a complete HTTP request in the body and cause SoupServer to process that smuggled request, leading to unintended request handling. (CVE-2026-103399)
An out-of-bounds read vulnerability was found in libsoup's multipart processing subsystem. The flaw exists in the soup_multipart_input_stream_read_headers() function inside soup-multipart-input-stream.c, which does not adequately restrict or validate the size of incoming multipart boundary strings. When processing a crafted HTTP response containing a malformed or oversized boundary parameter, the internal stream reader reads past the allocated buffer bounds. A remote, unauthenticated attacker can exploit this behavior to cause a service denial (DoS) through application failure or potentially read fragments of unauthorized memory metadata. (CVE-2026-15714)
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 ALAS2-2026-3998 to update your system.
aarch64:
libsoup-2.56.0-6.amzn2.0.10.aarch64
libsoup-devel-2.56.0-6.amzn2.0.10.aarch64
libsoup-debuginfo-2.56.0-6.amzn2.0.10.aarch64
i686:
libsoup-2.56.0-6.amzn2.0.10.i686
libsoup-devel-2.56.0-6.amzn2.0.10.i686
libsoup-debuginfo-2.56.0-6.amzn2.0.10.i686
src:
libsoup-2.56.0-6.amzn2.0.10.src
x86_64:
libsoup-2.56.0-6.amzn2.0.10.x86_64
libsoup-devel-2.56.0-6.amzn2.0.10.x86_64
libsoup-debuginfo-2.56.0-6.amzn2.0.10.x86_64