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CVE-2026-52993

CRITICAL 9.8

Published 2026-06-24 · Last modified 2026-07-15

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.

ELEVATED IMPACT

Severe if exploited (CVSS 9.8), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.4%chance of exploitation in 30 days · 28th percentile

○ In CISA KEV ○ Public exploit / PoC

Impact if exploited

9.8CVSS 3.1 · CRITICAL

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityHigh

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ✓Complexity: No special conditions — reliably repeatable

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept & exploit code

Test against your own equipment

curl -s https://vulnpedia.com/cve/CVE-2026-52993/poc.jsonMachine-readable PoC index for this CVE (for automation).

Listed for defensive triage, patch verification, and authorized testing on systems you own. Machine-readable: /cve/CVE-2026-52993/poc.json

Affected

Vendors Linux Red Hat

Products Linux Red Hat Enterprise Linux 10 Red Hat Enterprise Linux 6 Red Hat Enterprise Linux 7 Red Hat Enterprise Linux 8 Red Hat Enterprise Linux 9 Linux Kernel

Weakness (CWE)

  • CWE-763: Release of Invalid Pointer or Reference
  • CWE-415: Double Free

CVSS vector

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

Known Affected Software Configurations

VendorProductVersion range
LinuxLinux Kernel≥ 4.15 and < 5.10.258
LinuxLinux Kernel≥ 5.11 and < 5.15.209
LinuxLinux Kernel≥ 5.16 and < 6.1.175
LinuxLinux Kernel≥ 6.2 and < 6.6.141
LinuxLinux Kernel≥ 6.7 and < 6.12.91
LinuxLinux Kernel≥ 6.13 and < 6.18.33
LinuxLinux Kernel≥ 6.19 and < 7.0.10

All CVSS metrics

  • CRITICAL 9.8 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • HIGH 7 v3.1 · ADP Primary
    CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
  • CRITICAL 9.8 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
  • HIGH 7 v3.1 · NVD Secondary
    CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H

References

Patches & mitigations

Advisories

Sources: NVD · CVE.org · EPSS