CVE-2026-25068

The alsa-lib is a library to interface with ALSA in the Linux kernel and virtual devices using a plugin system. More detail: https://alsa.opensrc.org/Alsa-lib

Security Fix(es):

alsa-lib versions 1.2.2 up to and including 1.2.15.2, prior to commit 5f7fe33, contain a heap-based buffer overflow in the topology mixer control decoder. The tplg_decode_control_mixer1() function reads the num_channels field from untrusted .tplg data and uses it as a loop bound without validating it against the fixed-size channel array (SND_TPLG_MAX_CHAN). A crafted topology file with an excessive num_channels value can cause out-of-bounds heap writes, leading to a crash.(CVE-2026-25068)

alsa-lib versions 1.2.2 up to and including 1.2.15.2, prior to commit 5f7fe33, contain a heap-based buffer overflow in the topology mixer control decoder. The tplg_decode_control_mixer1() function reads the num_channels field from untrusted .tplg data and uses it as a loop bound without validating it against the fixed-size channel array (SND_TPLG_MAX_CHAN). A crafted topology file with an excessive num_channels value can cause out-of-bounds heap writes, leading to a crash.

alsa-lib versions 1.2.2 up to and including 1.2.15.2, prior to commit 5f7fe33, contain a heap-based buffer overflow in the topology mixer control decoder. The tplg_decode_control_mixer1() function reads the num_channels field from untrusted .tplg data and uses it as a loop bound without validating it against the fixed-size channel array (SND_TPLG_MAX_CHAN). A crafted topology file with an excessive num_channels value can cause out-of-bounds heap writes, leading to a crash.

alsa-lib versions 1.2.2 up to and including 1.2.15.2, prior to commit 5f7fe33, contain a heap-based buffer overflow in the topology mixer control decoder. The tplg_decode_control_mixer1() function reads the num_channels field from untrusted .tplg data and uses it as a loop bound without validating it against the fixed-size channel array (SND_TPLG_MAX_CHAN). A crafted topology file with an excessive num_channels value can cause out-of-bounds heap writes, leading to a crash.

alsa-lib 1.2.15.2 Topology Decoder Heap-based Buffer Overflow. (CVE-2026-25068) ALSA Library < 1.2.16.1 Double-Free via parse_def() in conf.c. (CVE-2026-56109)

It was discovered that alsa-lib incorrectly handled the topology mixer control decoder. A local attacker could use a specially crafted topology file to cause alsa-lib to crash, resulting in a denial of service, or possibly execute arbitrary code.

USN-8044-1 fixed a vulnerability in alsa-lib. This update provides the corresponding fix for alsa-lib on Ubuntu 20.04 LTS.

Original advisory details:

It was discovered that alsa-lib incorrectly handled the topology mixer control decoder. A local attacker could use a specially crafted topology file to cause alsa-lib to crash, resulting in a denial of service, or possibly execute arbitrary code.