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Vulnerability record · CVE-2026-52993 · published 24 June 2026

CVE-2026-52993: Linux kernel double free vulnerability

Linux · Linux Kernel

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.

9.8 CVSS 3.1 Critical EPSS 0.53% · top 57.6% CWE-415 · Double freeCWE-763 · CWE-763
9.8CVSS 3.1 base score
0.53%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
15References
3 Aug 2026Last modified by NVD

Description

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.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://git.kernel.org/stable/c/0274f24485fc38032d4093e463dc3ff5c7a667c9 Patch
https://git.kernel.org/stable/c/1d5e589055880fae229e229e1929e087dbe08cf3 Patch
https://git.kernel.org/stable/c/29940fff14110ca48c5ccc168d121665b51bb778 Patch
https://git.kernel.org/stable/c/4d104882bc815d4ec666ace9155f5f52715879a6 Patch
https://git.kernel.org/stable/c/4ee4deadaae7cb2e3d53af0fc889cf92a73413c0 Patch
https://git.kernel.org/stable/c/a438975a6dcdbd70865978c021650d1485586f0b Patch
https://git.kernel.org/stable/c/d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a Patch
https://git.kernel.org/stable/c/d3556656c6daebf8def751c7e71d11dd0a180d24 Patch
https://access.redhat.com/errata/RHSA-2026:45115
https://access.redhat.com/errata/RHSA-2026:45116
https://access.redhat.com/errata/RHSA-2026:47017
https://access.redhat.com/errata/RHSA-2026:49212
https://access.redhat.com/security/cve/CVE-2026-52993 Third Party Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2492437 Third Party Advisory
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52993.json Third Party Advisory

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Source: NIST National Vulnerability Database (record CVE-2026-52993), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.