CVE-2026-52993: tipc: fix double-free in tipc_buf_append()
Vulnerability summary
CVE-2026-52993 is a critical (CVSS 9.8) Double Free vulnerability in linux. EPSS estimates a 0.40% chance of exploitation in the next 30 days, higher than 34.6% of scored vulnerabilities.
Severe, CVSS 9.8 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 0% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 77 · Related 65Timeline
- 24-06-2026PublishedVulnerability first disclosed.
- 19-10-2026Last modifiedVulnerability information updated.
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 metrics
5 scores · 4 sources · 2 versions- OSV · UbuntuEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- OSV · DebianEcosystem advisory · calculated9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- NVDNIST9.8CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
EPSS trend
Probability
0.40%
Chance of exploitation in the next 30 days
Percentile
35%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.40% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Ubuntu165 products
- linux< 4.15.0-257.269 | < 5.4.0-234.254 | < 5.15.0-186.196 | < 6.8.0-136.136 | All versions (No fix recorded) | < 7.0.0-28.28
- linux-allwinner-5.19All versions (No fix recorded)
- linux-aws< 4.15.0-1196.209 | < 5.4.0-1162.173 | < 5.15.0-1112.119 | < 6.8.0-1061.64 | All versions (No fix recorded) | < 7.0.0-1009.9
- linux-aws-5.0All versions (No fix recorded)
- linux-aws-5.11All versions (No fix recorded)
Linux2 products
- linux≥ d618d09a68e4eed7a435beb2e355250f6f40664a, < a438975a6dcdbd70865978c021650d1485586f0b | ≥ d618d09a68e4eed7a435beb2e355250f6f40664a, < 4ee4deadaae7cb2e3d53af0fc889cf92a73413c0 | ≥ d618d09a68e4eed7a435beb2e355250f6f40664a, < d3556656c6daebf8def751c7e71d11dd0a180d24 | ≥ d618d09a68e4eed7a435beb2e355250f6f40664a, < 0274f24485fc38032d4093e463dc3ff5c7a667c9 | ≥ d618d09a68e4eed7a435beb2e355250f6f40664a, < 4d104882bc815d4ec666ace9155f5f52715879a6 | ≥ d618d09a68e4eed7a435beb2e355250f6f40664a, < 1d5e589055880fae229e229e1929e087dbe08cf3 | ≥ d618d09a68e4eed7a435beb2e355250f6f40664a, < 29940fff14110ca48c5ccc168d121665b51bb778 | ≥ d618d09a68e4eed7a435beb2e355250f6f40664a, < d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a | 4.15
- linux_kernel≥ 4.15, < 5.10.258 | ≥ 5.11, < 5.15.209 | ≥ 5.16, < 6.1.175 | ≥ 6.2, < 6.6.141 | ≥ 6.7, < 6.12.91 | ≥ 6.13, < 6.18.33 | ≥ 6.19, < 7.0.10
Debian1 product
- linux< 6.1.176-1 | < 6.12.94-1 | < 7.0.10-1
3 vendors · 168 products
References
69 linksShow all 69 references
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-52993.jsonX Sadp Csaf VexThird Party Advisory
