{"id":"CVE-2026-63831","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nmac802154: llsec: add skb_cow_data() before in-place crypto\n\nllsec_do_encrypt_unauth(), llsec_do_encrypt_auth(),\nllsec_do_decrypt_unauth(), and llsec_do_decrypt_auth() …","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nmac802154: llsec: add skb_cow_data() before in-place crypto\n\nllsec_do_encrypt_unauth(), llsec_do_encrypt_auth(),\nllsec_do_decrypt_unauth(), and llsec_do_decrypt_auth() …","severity":"high","cvss":8.8,"cvssVector":"CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H","published":"2026-07-19","updated":"2026-08-17","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-63831","references":[{"url":"https://git.kernel.org/stable/c/3a2b378b3a9ca75d3518d879148d2ad25b5714a9","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7a831bcd0486788283ef35e396d4282ee01bb0d5","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/84a04eb5b210643bd67aab81ff805d32f62aa865","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/86d531337ea1ba02d9f2bc830d07c683d9bfaade","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/993fd674fe85d114e6a8d3963033d4fbbc2170a8","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/bd968bdd568beacfdf98ec537a87527e85f1d0cf","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/e28e7fd34c449028325322a3f5127b92594b7396","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/ff976ef7c39199ebff33c18034636595016db9f0","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63831.json"},{"url":"https://access.redhat.com/security/cve/CVE-2026-63831"},{"url":"https://bugzilla.redhat.com/show_bug.cgi?id=2502243"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-63831"},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-63831"},{"url":"https://lore.kernel.org/linux-cve-announce/2026071908-CVE-2026-63831-36ca@gregkh/T"},{"url":"https://access.redhat.com/errata/RHSA-2026:71213"},{"url":"https://access.redhat.com/errata/RHSA-2026:71016"},{"url":"https://access.redhat.com/errata/RHSA-2026:88687"},{"url":"https://access.redhat.com/errata/RHSA-2026:71233"},{"url":"https://access.redhat.com/errata/RHSA-2026:71232"}],"tags":["nvd","csaf","vex","red-hat","cve.org"],"epss":0.00307,"epssPercentile":0.23387,"ingestedAt":"2026-08-17T05:47:50.444Z","vendor":"Red Hat","product":"Red Hat Enterprise Linux 9","affected":["enterprise_linux 10","enterprise_linux 9","enterprise_linux_baseos_v_8","enterprise_linux_crb_v_8","enterprise_linux_nfv_v_8","enterprise_linux_rt_v_8"],"patched":["enterprise_linux_baseos_v_8","enterprise_linux_crb_v_8","enterprise_linux_nfv_v_8","enterprise_linux_rt_v_8"],"cwe":["CWE-820"],"scores":{"nvd":8.8,"vendor":7,"cna":8.8},"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"total","timestamp":"2026-10-16T15:31:21.214861Z"},"slug":"CVE-2026-63831","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nmac802154: llsec: add skb_cow_data() before in-place crypto\n\nllsec_do_encrypt_unauth(), llsec_do_encrypt_auth(),\nllsec_do_decrypt_unauth(), and llsec_do_decrypt_auth() all perform\nin-place cryptographic transformations on skb data.  They build a\nscatterlist with sg_init_one() pointing into the skb's linear data area\nand then pass the same scatterlist as both src and dst to the crypto API\n(e.g. crypto_skcipher_encrypt/decrypt, crypto_aead_encrypt/decrypt).\n\nOn the RX path, __ieee802154_rx_handle_packet() clones the received skb\nbefore handing it to each subscriber via ieee802154_subif_frame().  The\ncloned skb shares the same underlying data buffer via reference\ncounting.  When llsec_do_decrypt() subsequently modifies this shared\nbuffer in place, it corrupts data that other clones -- potentially\nbelonging to other sockets or subsystems -- still reference.\n\nOn the TX path, similar data sharing can occur when an skb's head has\nbeen cloned (skb_cloned() returns true).\n\nThe fix is to call skb_cow_data() before performing any in-place crypto\noperation.  skb_cow_data() ensures that the skb's data area is not\nshared: if the skb head is cloned or the data spans multiple fragments,\nit copies the data into a private buffer that can be safely modified in\nplace.  This is the same pattern used by:\n\n  - ESP (net/ipv4/esp4.c, net/ipv6/esp6.c)\n  - MACsec (drivers/net/macsec.c)\n  - WireGuard (drivers/net/wireguard/receive.c)\n  - TIPC (net/tipc/crypto.c)\n\nWithout this guard, in-place crypto on shared skb data leads to:\n  - Silent data corruption of other skb clones\n  - Use-after-free when the crypto API scatterwalk writes through a\n    page that has already been freed by another clone's kfree_skb()\n  - Kernel crashes under concurrent 802.15.4 traffic with security\n    enabled (KASAN/KMSAN reports slab-use-after-free)\n\nFound by 0sec (https://0sec.ai) using automated source analysis.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Vendor advisories\n\n- **RHSA-2026:71213** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71213)\n- **RHSA-2026:71016** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:71016)\n- **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-10-23 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-63831.json)\n- **RHSA-2026:88687** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v. 10.0), Red Hat Enterprise Linux BaseOS EUS (v. 10.0), Red Hat Enterprise Linux CodeReady Linux Builder EUS (v. 10.0), Red Hat Enterprise Linux Real Time for NFV EUS (v. 10.0), Red Hat Enterprise Linux Real Time EUS (v. 10.0) · released 2026-10-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:88687)\n- **RHSA-2026:71233** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 10), Red Hat Enterprise Linux BaseOS (v. 10), Red Hat Enterprise Linux CodeReady Linux Builder (v. 10), Red Hat Enterprise Linux Real Time for NFV (v. 10), Red Hat Enterprise Linux Real Time (v. 10) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71233)\n- **RHSA-2026:71232** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream (v. 9), Red Hat Enterprise Linux BaseOS (v. 9), Red Hat Enterprise Linux CodeReady Linux Builder (v. 9), Red Hat Enterprise Linux Real Time for NFV (v. 9), Red Hat Enterprise Linux Real Time (v. 9) · released 2026-09-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:71232)","depth":"twilight","depthScore":48,"depthScoreParts":{"impact":48.4,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}