{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-43050", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-05-01T14:12:55.979Z", "datePublished": "2026-05-01T14:15:44.542Z", "dateUpdated": "2026-05-11T22:16:44.767Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T22:16:44.767Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\natm: lec: fix use-after-free in sock_def_readable()\n\nA race condition exists between lec_atm_close() setting priv->lecd\nto NULL and concurrent access to priv->lecd in send_to_lecd(),\nlec_handle_bridge(), and lec_atm_send(). When the socket is freed\nvia RCU while another thread is still using it, a use-after-free\noccurs in sock_def_readable() when accessing the socket's wait queue.\n\nThe root cause is that lec_atm_close() clears priv->lecd without\nany synchronization, while callers dereference priv->lecd without\nany protection against concurrent teardown.\n\nFix this by converting priv->lecd to an RCU-protected pointer:\n- Mark priv->lecd as __rcu in lec.h\n- Use rcu_assign_pointer() in lec_atm_close() and lecd_attach()\n for safe pointer assignment\n- Use rcu_access_pointer() for NULL checks that do not dereference\n the pointer in lec_start_xmit(), lec_push(), send_to_lecd() and\n lecd_attach()\n- Use rcu_read_lock/rcu_dereference/rcu_read_unlock in send_to_lecd(),\n lec_handle_bridge() and lec_atm_send() to safely access lecd\n- Use rcu_assign_pointer() followed by synchronize_rcu() in\n lec_atm_close() to ensure all readers have completed before\n proceeding. This is safe since lec_atm_close() is called from\n vcc_release() which holds lock_sock(), a sleeping lock.\n- Remove the manual sk_receive_queue drain from lec_atm_close()\n since vcc_destroy_socket() already drains it after lec_atm_close()\n returns.\n\nv2: Switch from spinlock + sock_hold/put approach to RCU to properly\n fix the race. The v1 spinlock approach had two issues pointed out\n by Eric Dumazet:\n 1. priv->lecd was still accessed directly after releasing the\n lock instead of using a local copy.\n 2. The spinlock did not prevent packets being queued after\n lec_atm_close() drains sk_receive_queue since timer and\n workqueue paths bypass netif_stop_queue().\n\nNote: Syzbot patch testing was attempted but the test VM terminated\n unexpectedly with \"Connection to localhost closed by remote host\",\n likely due to a QEMU AHCI emulation issue unrelated to this fix.\n Compile testing with \"make W=1 net/atm/lec.o\" passes cleanly." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/atm/lec.c", "net/atm/lec.h" ], "versions": [ { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "3e8b25f32f2f35549d03d77da030a24a45bdef5b", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "750a33f417f3d196b86375f8d9f8938bacf130fe", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "317843d5355062020649124eb4a0d7acbcc3f53e", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "b256d055da47258e63f8b40965f276c5f23d229a", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "3989740fa4978e1d2d51ecc62be1b01093e104ad", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "abc10f85a3965ac14b9ed7ad3e67b35604a63aa3", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "5fbbb1ff936d7ff9528d929c1549977e8123d8a8", "status": "affected", "versionType": "git" }, { "version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2", "lessThan": "922814879542c2e397b0e9641fd36b8202a8e555", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/atm/lec.c", "net/atm/lec.h" ], "versions": [ { "version": "2.6.12", "status": "affected" }, { "version": "0", "lessThan": "2.6.12", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.253", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.203", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.168", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.134", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.81", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.22", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.19.12", "lessThanOrEqual": "6.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.0", "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": "2.6.12", "versionEndExcluding": "5.10.253" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "5.15.203" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.1.168" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.6.134" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.12.81" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.18.22" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "6.19.12" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.12", "versionEndExcluding": "7.0" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/3e8b25f32f2f35549d03d77da030a24a45bdef5b" }, { "url": "https://git.kernel.org/stable/c/750a33f417f3d196b86375f8d9f8938bacf130fe" }, { "url": "https://git.kernel.org/stable/c/317843d5355062020649124eb4a0d7acbcc3f53e" }, { "url": "https://git.kernel.org/stable/c/b256d055da47258e63f8b40965f276c5f23d229a" }, { "url": "https://git.kernel.org/stable/c/3989740fa4978e1d2d51ecc62be1b01093e104ad" }, { "url": "https://git.kernel.org/stable/c/abc10f85a3965ac14b9ed7ad3e67b35604a63aa3" }, { "url": "https://git.kernel.org/stable/c/5fbbb1ff936d7ff9528d929c1549977e8123d8a8" }, { "url": "https://git.kernel.org/stable/c/922814879542c2e397b0e9641fd36b8202a8e555" } ], "title": "atm: lec: fix use-after-free in sock_def_readable()", "x_generator": { "engine": "bippy-1.2.0" } } } }