Bug 2492437 (CVE-2026-52993)

Summary: CVE-2026-52993 kernel: tipc: fix double-free in tipc_buf_append()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
Status: NEW --- QA Contact:
Severity: high Docs Contact:
Priority: high    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's Transparent Inter-Process Communication (TIPC) module. This vulnerability, a double-free, occurs when the `tipc_buf_append()` function incorrectly handles memory after a socket buffer (skb) reallocation. An attacker could potentially exploit this to cause system instability or a denial of service. In some scenarios, this type of memory corruption could also lead to arbitrary code execution.
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Description OSIDB Bzimport 2026-06-24 18:12:03 UTC 
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.
Comment 1 Keith Grant 2026-06-25 21:09:15 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062445-CVE-2026-52993-34a2@gregkh/T
Comment 3 errata-xmlrpc 2026-07-24 09:59:05 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:45115 https://access.redhat.com/errata/RHSA-2026:45115
Comment 4 errata-xmlrpc 2026-07-24 09:59:08 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:45116 https://access.redhat.com/errata/RHSA-2026:45116
Comment 5 errata-xmlrpc 2026-07-28 06:29:38 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:47017 https://access.redhat.com/errata/RHSA-2026:47017
Comment 6 errata-xmlrpc 2026-07-31 20:44:38 UTC 
This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:49212 https://access.redhat.com/errata/RHSA-2026:49212