--- id: CVE-2026-52993 title: |- In the Linux kernel, the following vulnerability has been resolved: tipc: fix double-free in tipc_buf_append() tipc_msg_validate() can potentially reallocate the skb it is validating, freeing the old one summary: |- In the Linux kernel, the following vulnerability has been resolved: tipc: fix double-free in tipc_buf_append() tipc_msg_validate() can potentially reallocate the skb it is validating, freeing the old one. In tipc_buf_append(), it was … severity: critical cvss: 9.8 cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H' cwe: - CWE-763 published: '2026-06-24' updated: '2026-07-10' source: NVD sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-52993' references: - url: 'https://git.kernel.org/stable/c/0274f24485fc38032d4093e463dc3ff5c7a667c9' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/1d5e589055880fae229e229e1929e087dbe08cf3' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/29940fff14110ca48c5ccc168d121665b51bb778' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/4d104882bc815d4ec666ace9155f5f52715879a6' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/4ee4deadaae7cb2e3d53af0fc889cf92a73413c0' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/a438975a6dcdbd70865978c021650d1485586f0b' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://git.kernel.org/stable/c/d3556656c6daebf8def751c7e71d11dd0a180d24' label: 416baaa9-dc9f-4396-8d5f-8c081fb06d67 - url: 'https://access.redhat.com/security/cve/CVE-2026-52993' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2492437' label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: >- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52993.json label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c - url: 'https://www.cve.org/CVERecord?id=CVE-2026-52993' - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-52993' - url: >- https://lore.kernel.org/linux-cve-announce/2026062445-CVE-2026-52993-34a2@gregkh/T - url: 'https://access.redhat.com/errata/RHSA-2026:47017' - url: 'https://access.redhat.com/errata/RHSA-2026:49212' - url: 'https://access.redhat.com/errata/RHSA-2026:45115' - url: 'https://access.redhat.com/errata/RHSA-2026:69837' - url: 'https://access.redhat.com/errata/RHSA-2026:45116' - url: 'https://access.redhat.com/errata/RHSA-2026:70482' - url: 'https://access.redhat.com/errata/RHSA-2026:69874' - url: 'https://access.redhat.com/errata/RHSA-2026:69906' - url: 'https://access.redhat.com/errata/RHSA-2026:70483' - url: 'https://access.redhat.com/errata/RHSA-2026:73645' - url: 'https://access.redhat.com/errata/RHSA-2026:75560' - url: 'https://access.redhat.com/errata/RHSA-2026:74174' tags: - nvd - csaf - vex - red-hat - exploit-available - cve.org - score-dispute epss: 0.00404 epssPercentile: 0.3445 ingestedAt: '2026-07-11T13:13:25.646Z' vendor: Red Hat product: Red Hat Enterprise Linux BaseOS (v. 10) affected: - enterprise_linux 9 - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_e4s_v_8_8 - enterprise_linux_baseos_tus_v_8_8 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_crb_v_8 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_v_10 - enterprise_linux_rt_v_8 - enterprise_linux_real_time_v_9 patched: - enterprise_linux_appstream_v_10 - enterprise_linux_appstream_v_9 - enterprise_linux_baseos_v_10 - enterprise_linux_baseos_v_8 - enterprise_linux_baseos_e4s_v_8_8 - enterprise_linux_baseos_tus_v_8_8 - enterprise_linux_baseos_v_9 - enterprise_linux_codeready_linux_builder_v_10 - enterprise_linux_crb_v_8 - enterprise_linux_codeready_linux_builder_v_9 - enterprise_linux_real_time_for_nfv_v_10 - enterprise_linux_nfv_v_8 - enterprise_linux_real_time_for_nfv_v_9 - enterprise_linux_real_time_v_10 - enterprise_linux_rt_v_8 - enterprise_linux_real_time_v_9 scores: nvd: 9.8 vendor: 7 cna: 9.8 exploits: github: 1 githubRepos: - 'https://github.com/CaptainAI-Labs/CaptainAI-LPE-CVE-2026-52993' checkedAt: '2026-10-27T19:02:54.152Z' exploitAvailable: true ssvc: exploitation: none automatable: 'yes' technicalImpact: total timestamp: '2026-10-16T15:24:18.442775Z' --- ## Overview In the Linux kernel, the following vulnerability has been resolved: tipc: fix double-free in tipc_buf_append() tipc_msg_validate() can potentially reallocate the skb it is validating, freeing the old one. In tipc_buf_append(), it was being called with a pointer to a local variable which was a copy of the caller's skb pointer. If the skb was reallocated and validation subsequently failed, the error handling path would free the original skb pointer, which had already been freed, leading to double-free. Fix this by checking if head now points to a newly allocated reassembled skb. If it does, reassign *headbuf for later freeing operations. ## Remediation Refer to the linked advisories for vendor-supplied fixes and affected version ranges. ## Vendor advisories - **RHSA-2026:47017** · 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 2026-07-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:47017) - **RHSA-2026:49212** · 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 2026-07-31 · [advisory](https://access.redhat.com/errata/RHSA-2026:49212) - **RHSA-2026:45115** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS (v. 8), Red Hat Enterprise Linux CRB (v. 8) · released 2026-07-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:45115) - **RHSA-2026:69837** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS E4S (v.8.8), Red Hat Enterprise Linux BaseOS TUS (v.8.8) · released 2026-09-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:69837) - **RHSA-2026:45116** · Red Hat · fixed in: Red Hat Enterprise Linux NFV (v. 8), Red Hat Enterprise Linux RT (v. 8) · released 2026-07-24 · [advisory](https://access.redhat.com/errata/RHSA-2026:45116) - **Red Hat VEX** · Important · affected: Red Hat Enterprise Linux 9 · no fix planned: Red Hat Enterprise Linux 9 · updated 2026-10-05 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52993.json) - **RHSA-2026:70482** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.2), Red Hat Enterprise Linux BaseOS E4S (v.9.2) · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:70482) - **RHSA-2026:69874** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS AUS (v.8.4), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.4) · released 2026-09-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:69874) - **RHSA-2026:69906** · Red Hat · fixed in: Red Hat Enterprise Linux BaseOS AUS (v.8.6), Red Hat Enterprise Linux BaseOS EUS EXTENSION (v.8.6) · released 2026-09-22 · [advisory](https://access.redhat.com/errata/RHSA-2026:69906) - **RHSA-2026:70483** · Red Hat · fixed in: Red Hat Enterprise Linux Real Time for NFV E4S (v.9.2), Red Hat Enterprise Linux Real Time E4S (v.9.2) · released 2026-09-23 · [advisory](https://access.redhat.com/errata/RHSA-2026:70483) - **RHSA-2026:73645** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream E4S (v.9.4), Red Hat Enterprise Linux BaseOS E4S (v.9.4), Red Hat Enterprise Linux Real Time for NFV E4S (v.9.4), Red Hat Enterprise Linux Real Time E4S (v.9.4) · released 2026-09-30 · [advisory](https://access.redhat.com/errata/RHSA-2026:73645) - **RHSA-2026:75560** · 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 2026-10-05 · [advisory](https://access.redhat.com/errata/RHSA-2026:75560) - **RHSA-2026:74174** · Red Hat · fixed in: Red Hat Enterprise Linux AppStream EUS (v.9.6), Red Hat Enterprise Linux BaseOS EUS (v.9.6), Red Hat CodeReady Linux Builder EUS (v.9.6), Red Hat Enterprise Linux Real Time for NFV EUS (v.9.6), Red Hat Enterprise Linux Real Time EUS (v.9.6) · released 2026-10-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:74174)