{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-23191", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-01-13T15:37:45.985Z", "datePublished": "2026-02-14T16:27:18.882Z", "dateUpdated": "2026-08-05T12:20:33.747Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T12:20:33.747Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nALSA: aloop: Fix racy access at PCM trigger\n\nThe PCM trigger callback of aloop driver tries to check the PCM state\nand stop the stream of the tied substream in the corresponding cable.\nSince both check and stop operations are performed outside the cable\nlock, this may result in UAF when a program attempts to trigger\nfrequently while opening/closing the tied stream, as spotted by\nfuzzers.\n\nFor addressing the UAF, this patch changes two things:\n- It covers the most of code in loopback_check_format() with\n cable->lock spinlock, and add the proper NULL checks. This avoids\n already some racy accesses.\n- In addition, now we try to check the state of the capture PCM stream\n that may be stopped in this function, which was the major pain point\n leading to UAF." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "baseScore": 7.8, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:L - The vulnerability is in the ALSA aloop PCM driver, accessed through local sound device files (/dev/snd/pcmC*D*p and /dev/snd/pcmC*D*c). No network or adjacent access path exists.\nAC:L - The attacker fully controls both sides of the race condition — they can concurrently trigger PCM start on one substream while closing the paired substream. The race is reliably winnable by the attacker, as confirmed by syzbot reproducibility.\nPR:L - Accessing ALSA PCM device files requires a local unprivileged user with audio group membership or equivalent permissions, which is standard on desktop Linux and Android. The snd-aloop module must be loaded, but no root/admin privileges are required to trigger the bug once available.\nUI:N - No user interaction is required. The attacker can open, trigger, and close PCM substreams entirely on their own.\nS:U - The vulnerability and its impact remain within the kernel's security authority. There is no crossing of a security boundary such as a VM escape or sandbox escape.\nC:H - This is a use-after-free vulnerability where freed loopback_pcm and runtime structures are dereferenced. An attacker can reclaim the freed memory with controlled data, enabling arbitrary kernel memory reads.\nI:H - The UAF allows the attacker to reclaim freed heap objects via heap spraying, providing arbitrary write primitives and potential control flow hijacking through corrupted function pointers in the loopback_pcm or runtime structures.\nA:H - The use-after-free reliably causes kernel crashes (oops/panic) when the freed memory is accessed, as demonstrated by the syzbot fuzzer report." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "sound/drivers/aloop.c" ], "versions": [ { "version": "b1c73fc8e697eb73e23603e465e9af2711ed4183", "lessThan": "bad15420050db1803767e58756114800cce91ea4", "status": "affected", "versionType": "git" }, { "version": "b1c73fc8e697eb73e23603e465e9af2711ed4183", "lessThan": "5727ccf9d19ca414cb76d9b647883822e2789c2e", "status": "affected", "versionType": "git" }, { "version": "b1c73fc8e697eb73e23603e465e9af2711ed4183", "lessThan": "826af7fa62e347464b1b4e0ba2fe19a92438084f", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "sound/drivers/aloop.c" ], "versions": [ { "version": "2.6.37", "status": "affected" }, { "version": "0", "lessThan": "2.6.37", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.70", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.10", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.12.70" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.18.10" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.37", "versionEndExcluding": "6.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/bad15420050db1803767e58756114800cce91ea4" }, { "url": "https://git.kernel.org/stable/c/5727ccf9d19ca414cb76d9b647883822e2789c2e" }, { "url": "https://git.kernel.org/stable/c/826af7fa62e347464b1b4e0ba2fe19a92438084f" } ], "title": "ALSA: aloop: Fix racy access at PCM trigger", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2026-06-16T20:20:28.206628Z", "id": "CVE-2026-23191", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "total" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2026-06-16T20:20:36.627Z" } } ] } }