Critical Memory corruption

CVE-2026-52993 — Linux kernel TIPC double-free in tipc_buf_append()

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.

Published Jun 24, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.4% (30-day exploitation probability)+5
Technical severity (critical)+10

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.4%

ahead of 33% of scored CVEs · Oct 14, 2026

Affects

Linux

Linux and 1 more

CVSS base

9.8

Critical · 3 source(s)

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)
Documented patch — git.kernel.org (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Linux Linux, Linux Linux Kernel).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the fixed version or the patch documented under Remediation.
Search available logs for exploit probes matching the vulnerability class (memory corruption), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Linux	Linux	≥ d618d09a68e4eed7a435beb2e355250f6f40664a and < a438975a6dcdbd70865978c021650d1485586f0b≥ d618d09a68e4eed7a435beb2e355250f6f40664a and < 4ee4deadaae7cb2e3d53af0fc889cf92a73413c0≥ d618d09a68e4eed7a435beb2e355250f6f40664a and < d3556656c6daebf8def751c7e71d11dd0a180d24≥ d618d09a68e4eed7a435beb2e355250f6f40664a and < 0274f24485fc38032d4093e463dc3ff5c7a667c9≥ d618d09a68e4eed7a435beb2e355250f6f40664a and < 4d104882bc815d4ec666ace9155f5f52715879a6≥ d618d09a68e4eed7a435beb2e355250f6f40664a and < 1d5e589055880fae229e229e1929e087dbe08cf3≥ d618d09a68e4eed7a435beb2e355250f6f40664a and < 29940fff14110ca48c5ccc168d121665b51bb778≥ d618d09a68e4eed7a435beb2e355250f6f40664a and < d293ca716e7d5dffdaecaf6b9b2f857a33dc3d3a and 1 more version 4.15	Vulnerable	CVE Program (cve.org) e CISA ADP
Linux	Linux Kernel	≥ 4.15 and < 5.10.258≥ 5.11 and < 5.15.209≥ 5.16 and < 6.1.175≥ 6.2 and < 6.6.141≥ 6.7 and < 6.12.91≥ 6.13 and < 6.18.33≥ 6.19 and < 7.0.10	Vulnerable	NIST National Vulnerability Database

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

None

Scope

Unchanged

Confidentiality

High

Integrity

High

Availability

High

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
9.8	CVSS 3.1	Critical	3.9	5.9	416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database
9.8	CVSS 3.1	Critical	—	—	Linux via CVE Program (cve.org) e CISA ADP
7.0	CVSS 3.1	High	1.0	5.9	0b0ca135-0b70-47e7-9f44-1890c2a1c46c via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H (score shown at the top: 416baaa9-dc9f-4396-8d5f-8c081fb06d67)

Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 9.8 (416baaa9-dc9f-4396-8d5f-8c081fb06d67 via NIST National Vulnerability Database) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-415 · Double Free

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.40%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Correlate service crashes/restarts with inbound traffic; repeated crashes may indicate attempts.

web/proxy/WAF logsnetwork IDS/IPSendpoint telemetry (EDR)crash dumps

Analysis and videos

CVE-2026-52993: Linux kernel TIPC double-free in tipc_buf_append()
CVE-2026-52993 is a double-free (CWE-415) in the TIPC networking code of the Linux kernel, in tipc_buf_append(). The CNA rates it 9.8 (CVSS 3.1), and the record also lists a 7.0 score from another provider. The record lists affected kernel version ranges and stable-kernel fixes, and it does not list the CVE in CISA KEV.

Timeline

What happened to this CVE, newest first.

2026
Affected products added · linux/linux
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 9.8
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Jun 24, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

15 on the record

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

Elsewhere on this site

Linux
every CVE for this vendor

Memory corruption
same class

CWE-415
other pages naming this weakness

Related CVEs (same products)

Critical CVE-2026-99999 ipv4: validate checksum_start before completing checksum 12h
Unknown CVE-2026-98432 ipv4: free inet_opt and ireq_opt after an RCU grace period 12h
Unknown CVE-2026-98424 wifi: cfg80211: undo netns switch if renaming the wiphy fails 1d
Unknown CVE-2026-98425 wifi: mac80211: don't warn when an IBSS has no channel to scan 1d
Unknown CVE-2026-98426 wifi: mwifiex: fix IRQ leak using wrong index in MSI-X error path 1d
Unknown CVE-2026-98427 net/sched: codel: bound the dropping loop per dequeue call 1d

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No CISA SSVC assessment.
No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-52993 is "Linux kernel TIPC double-free in tipc_buf_append()", rated Critical. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 9.8 describes technical severity. EPSS 0.40% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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