{"id":"CVE-2026-23419","state":"PUBLISHED","title":"net/rds: Fix circular locking dependency in rds_tcp_tune","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: Fix circular locking dependency in rds_tcp_tune\n\nsyzbot reported a circular locking dependency in rds_tcp_tune() where\nsk_net_refcnt_upgrade() is called while holding the socket lock:\n\n======================================================\nWARNING: possible circular locking dependency detected\n======================================================\nkworker/u10:8/15040 is trying to acquire lock:\nffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0},\nat: __kmalloc_cache_noprof+0x4b/0x6f0\n\nbut task is already holding lock:\nffff88805a3c1ce0 (k-sk_lock-AF_INET6){+.+.}-{0:0},\nat: rds_tcp_tune+0xd7/0x930\n\nThe issue occurs because sk_net_refcnt_upgrade() performs memory\nallocation (via get_net_track() -> ref_tracker_alloc()) while the\nsocket lock is held, creating a circular dependency with fs_reclaim.\n\nFix this by moving sk_net_refcnt_upgrade() outside the socket lock\ncritical section. This is safe because the fields modified by the\nsk_net_refcnt_upgrade() call (sk_net_refcnt, ns_tracker) are not\naccessed by any concurrent code path at this point.\n\nv2:\n  - Corrected fixes tag\n  - check patch line wrap nits\n  - ai commentary nits","publishedAt":"2026-04-03T13:24:23.958Z","updatedAt":"2026-10-30T12:24:06.599Z","severity":{"score":7.5,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"ce5be6703afd2ac2ff7dabd397137d71d22d4bc3","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"8babb271403378ba6836f6c8599c5313d0e2355d","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"8519e6883a942e510f33a0e634e27bcc3a844a40","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"6ce948fa54599f369ff7fe8b793a6aae4b0762b2","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"026bbaeeab9e04534ee58882b6447300629b42f6","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"6a877ececd6daa002a9a0002cd0fbca6592a9244","versionType":"git"},{"version":"2a6efabed754c9dcf27e6def71317b374f58a852","status":"affected","versionType":"git"},{"version":"5.17.7","status":"affected","lessThan":"5.18","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/tcp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.130","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.77","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.17","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.7","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/tcp.c"]}],"references":["https://git.kernel.org/stable/c/ce5be6703afd2ac2ff7dabd397137d71d22d4bc3","https://git.kernel.org/stable/c/8babb271403378ba6836f6c8599c5313d0e2355d","https://git.kernel.org/stable/c/8519e6883a942e510f33a0e634e27bcc3a844a40","https://git.kernel.org/stable/c/6ce948fa54599f369ff7fe8b793a6aae4b0762b2","https://git.kernel.org/stable/c/026bbaeeab9e04534ee58882b6447300629b42f6","https://git.kernel.org/stable/c/6a877ececd6daa002a9a0002cd0fbca6592a9244"],"weaknesses":[],"ingestedAt":"2026-10-30T12:40:04.423Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/23xxx/CVE-2026-23419.json","commit":"db8103c5921aac81d5d90efcf3745980dafabf49","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-23419","state":"PUBLISHED","datePublished":"2026-04-03T13:24:23.958Z","dateUpdated":"2026-10-30T12:24:06.599Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-01-13T15:37:46.014Z"},"containers":{"cna":{"title":"net/rds: Fix circular locking dependency in rds_tcp_tune","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet/rds: Fix circular locking dependency in rds_tcp_tune\n\nsyzbot reported a circular locking dependency in rds_tcp_tune() where\nsk_net_refcnt_upgrade() is called while holding the socket lock:\n\n======================================================\nWARNING: possible circular locking dependency detected\n======================================================\nkworker/u10:8/15040 is trying to acquire lock:\nffffffff8e9aaf80 (fs_reclaim){+.+.}-{0:0},\nat: __kmalloc_cache_noprof+0x4b/0x6f0\n\nbut task is already holding lock:\nffff88805a3c1ce0 (k-sk_lock-AF_INET6){+.+.}-{0:0},\nat: rds_tcp_tune+0xd7/0x930\n\nThe issue occurs because sk_net_refcnt_upgrade() performs memory\nallocation (via get_net_track() -> ref_tracker_alloc()) while the\nsocket lock is held, creating a circular dependency with fs_reclaim.\n\nFix this by moving sk_net_refcnt_upgrade() outside the socket lock\ncritical section. This is safe because the fields modified by the\nsk_net_refcnt_upgrade() call (sk_net_refcnt, ns_tracker) are not\naccessed by any concurrent code path at this point.\n\nv2:\n  - Corrected fixes tag\n  - check patch line wrap nits\n  - ai commentary nits"}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"ce5be6703afd2ac2ff7dabd397137d71d22d4bc3","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"8babb271403378ba6836f6c8599c5313d0e2355d","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"8519e6883a942e510f33a0e634e27bcc3a844a40","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"6ce948fa54599f369ff7fe8b793a6aae4b0762b2","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"026bbaeeab9e04534ee58882b6447300629b42f6","versionType":"git"},{"version":"3a58f13a881ed351198ffab4cf9953cf19d2ab3a","status":"affected","lessThan":"6a877ececd6daa002a9a0002cd0fbca6592a9244","versionType":"git"},{"version":"2a6efabed754c9dcf27e6def71317b374f58a852","status":"affected","versionType":"git"},{"version":"5.17.7","status":"affected","lessThan":"5.18","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/tcp.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"5.18","status":"affected"},{"version":"0","status":"unaffected","lessThan":"5.18","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.130","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.77","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.17","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"6.19.7","status":"unaffected","lessThanOrEqual":"6.19.*","versionType":"semver"},{"version":"7.0","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["net/rds/tcp.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/ce5be6703afd2ac2ff7dabd397137d71d22d4bc3"},{"url":"https://git.kernel.org/stable/c/8babb271403378ba6836f6c8599c5313d0e2355d"},{"url":"https://git.kernel.org/stable/c/8519e6883a942e510f33a0e634e27bcc3a844a40"},{"url":"https://git.kernel.org/stable/c/6ce948fa54599f369ff7fe8b793a6aae4b0762b2"},{"url":"https://git.kernel.org/stable/c/026bbaeeab9e04534ee58882b6447300629b42f6"},{"url":"https://git.kernel.org/stable/c/6a877ececd6daa002a9a0002cd0fbca6592a9244"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:N - RDS/TCP creates a listener on TCP port 16385, and an unauthenticated remote TCP connection reaches rds_tcp_accept_one() and rds_tcp_tune() before protocol-level validation. A local AF_RDS path also exists, but the highest reasonable vector is network.\nAC:L - The attacker can repeatedly trigger the vulnerable lock ordering by opening RDS/TCP connections; no special packet format, credentials, or attacker-uncontrolled race is needed to reach the bad allocation-under-socket-lock path. Applying the higher-severity rule, this is Low complexity.\nPR:N - The network accept path requires no local account, capabilities, or RDS authentication before rds_tcp_tune() is invoked. Remote reachability to the RDS/TCP listener is sufficient in a reasonable affected deployment.\nUI:N - No victim user action is required. The attacker can initiate the connection directly.\nS:U - The issue affects kernel locking within the same host security authority. It does not cross a VM, container, IOMMU, or other separate security scope boundary.\nC:N - The bug is a circular locking dependency involving sk_lock, sk_net_refcnt_upgrade(), ref_tracker allocation, and fs_reclaim. It does not expose kernel memory or create a read primitive.\nI:N - There is no memory corruption or write primitive; the fix only moves a refcount-tracker allocation outside the socket lock. Integrity is not directly impacted.\nA:H - The lock inversion can lead to a kernel deadlock or system hang, and syzbot reported it as a possible deadlock in the RDS accept worker. Kernel deadlock is High availability impact."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:24:06.599Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.6.130"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.12.77"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.18.17"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"6.19.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.18","versionEndExcluding":"7.0"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.17.7"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}