{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2026-90057", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-11T19:38:34.784Z", "datePublished": "2026-09-17T16:05:41.670Z", "dateUpdated": "2026-10-19T08:57:14.597Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T08:57:14.597Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nslip: remove slip_hangup() to fix use-after-free in slip_receive_buf()\n\nJaeyoung Chung and Eulgyu Kim reported a slab-use-after-free read\nin slip_receive_buf() when racing against tty hangup.\n\ntty_ldisc_hangup() calls ld->ops->hangup() while holding only\na read lock on tty->ldisc_sem (via tty_ldisc_ref()).\nBecause slip_hangup() simply called slip_close(), it ran concurrently\nwith reader functions such as slip_receive_buf().\n\nslip_close() unregisters and frees the net device and its private\nstruct slip, causing concurrent reader threads in slip_receive_buf()\nto dereference freed memory.\n\nLine discipline close() is already guaranteed to be called under\nthe write lock of tty->ldisc_sem during hangup processing\n(in tty_ldisc_reinit() or tty_ldisc_kill()).\n\nRemove slip_hangup() so teardown is serialized cleanly by slip_close()." } ], "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 UAF is reached by racing local TTY syscalls: ioctl(TIOCSETD, N_SLIP) then write() on a PTY master into pty_write→tty_insert_flip_string_and_push_buffer→flush_to_ldisc→tty_port_default_receive_buf→slip_receive_buf, while close() of that master runs pty_close→tty_vhangup→tty_ldisc_hangup→slip_hangup. Hangup is a local TTY lifecycle event, not bytes from a remote SLIP peer.\nAC:L - The attacker owns both PTY fds and can loop write() on the master (driving slip_receive_buf under tty_ldisc_ref()'s read lock) concurrently with close()→pty_close→tty_vhangup→slip_hangup, which tty_ldisc_hangup() also invokes under only a read lock. Because hangup() is not serialized by ldisc_sem's write side, the attacker creates and retries the race.\nPR:L - Attaching N_SLIP requires slip_open()'s capable(CAP_NET_ADMIN) check, which is ns_capable(&init_user_ns) and is not granted by unshare -Urn. CAP_NET_ADMIN in the initial user namespace is still routinely given to non-root container/network workloads (Docker/K8s --cap-add=NET_ADMIN) without full host root, so privileges required are Low.\nUI:N - The attacker performs every step in its own processes: open(\"/dev/ptmx\"), ioctl(TIOCSETD, N_SLIP), write() to the master, and close() to force pty_close()→tty_vhangup(). No separate victim user or administrator action is required at exploit time.\nS:U - The UAF corrupts the host-kernel net_device allocated in sl_alloc() via alloc_netdev() and its embedded struct slip (netdev_priv). Impact is standard local kernel privilege escalation, not a VM escape or IOMMU/DMA boundary bypass.\nC:H - slip_receive_buf() loads sl from tty->disc_data without an RCU read-side critical section, then reads sl->magic and sl->dev after slip_hangup()→slip_close()→unregister_netdev() has freed that net_device (needs_free_netdev). A use-after-free of this object enables an arbitrary kernel read via heap spray.\nI:H - Once past those checks, slip_receive_buf() takes spin_lock_bh(&sl->lock) and slip_unesc() writes sl->rbuff[sl->rcount++] and sl->flags on the already-freed struct slip, giving a write primitive against a net_device that also carries netdev_ops function pointers.\nA:H - Use-after-free of the SLIP net_device/struct slip causes a kernel oops or panic even when not fully exploited; the report is a KASAN slab-use-after-free read in slip_receive_buf() racing tty hangup." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/slip/slip.c" ], "versions": [ { "version": "5342b77c4123ba39f911d92a813295fb3bb21f69", "lessThan": "9a3b1edff1ecb47d323f2506b3ffc22178acd1c6", "status": "affected", "versionType": "git" }, { "version": "5342b77c4123ba39f911d92a813295fb3bb21f69", "lessThan": "a2dbac3fb03b4427ccf057debc83fc61ee102529", "status": "affected", "versionType": "git" }, { "version": "5342b77c4123ba39f911d92a813295fb3bb21f69", "lessThan": "de1f978c0f6ab42b28192d74dc59af52fdc76135", "status": "affected", "versionType": "git" }, { "version": "5342b77c4123ba39f911d92a813295fb3bb21f69", "lessThan": "ddbc5dc5a2e29b3934da09c1ba3c930fd8a40fd6", "status": "affected", "versionType": "git" }, { "version": "5342b77c4123ba39f911d92a813295fb3bb21f69", "lessThan": "a540a49fcca59d1c92c3a6462e67ca21676a88df", "status": "affected", "versionType": "git" }, { "version": "5342b77c4123ba39f911d92a813295fb3bb21f69", "lessThan": "23c53269f2baaedf2d92784290cb9ef6db2a3bce", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "drivers/net/slip/slip.c" ], "versions": [ { "version": "2.6.32", "status": "affected" }, { "version": "0", "lessThan": "2.6.32", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.188", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.157", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.110", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.18.52", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.2.6", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver" }, { "version": "7.3", "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": "2.6.32", "versionEndExcluding": "6.1.188" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "6.6.157" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "6.12.110" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "6.18.52" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "7.2.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.32", "versionEndExcluding": "7.3" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/9a3b1edff1ecb47d323f2506b3ffc22178acd1c6" }, { "url": "https://git.kernel.org/stable/c/a2dbac3fb03b4427ccf057debc83fc61ee102529" }, { "url": "https://git.kernel.org/stable/c/de1f978c0f6ab42b28192d74dc59af52fdc76135" }, { "url": "https://git.kernel.org/stable/c/ddbc5dc5a2e29b3934da09c1ba3c930fd8a40fd6" }, { "url": "https://git.kernel.org/stable/c/a540a49fcca59d1c92c3a6462e67ca21676a88df" }, { "url": "https://git.kernel.org/stable/c/23c53269f2baaedf2d92784290cb9ef6db2a3bce" } ], "title": "slip: remove slip_hangup() to fix use-after-free in slip_receive_buf()", "x_generator": { "engine": "bippy-1.2.0" } } } }