CVE-2026-23444
Published: 03 April 2026
Summary
CVE-2026-23444 is a high-severity Missing Release of Memory after Effective Lifetime (CWE-401) vulnerability in Linux Linux Kernel. Its CVSS base score is 7.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked at the 4.9th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified are NIST 800-53 RA-5 (Vulnerability Monitoring and Scanning) and SI-2 (Flaw Remediation).
Deeper analysis
CVE-2026-23444 is a vulnerability in the Linux kernel's mac80211 Wi-Fi subsystem, specifically in the ieee80211_tx_prepare_skb() function. This function has three error paths, but only two free the socket buffer (skb); the first error path, triggered by ieee80211_tx_prepare() returning TX_DROP, does not free it. This inconsistency affects kernel drivers such as ath9k, mt76, and mac80211_hwsim, potentially leading to memory leaks as indicated by CWE-401. The issue was published on 2026-04-03 with a CVSS v3.1 base score of 7.8 (AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H).
A local attacker with low privileges can exploit this vulnerability with low attack complexity and no user interaction required. Successful exploitation could result in high impacts to confidentiality, integrity, and availability, likely through memory corruption stemming from the unfreed skb or related handling issues in the Wi-Fi transmit preparation process.
Mitigation involves applying the upstream kernel patches referenced in the stable git commits, including 06e769dddcbeb3baf2ce346273b53dd61fdbecf4, 3b4d27acafaeab478fd24f79ad6e593a892828b9, 50f1b690b4868923fbd242298def2fb88662f108, d5ad6ab61cbd89afdb60881f6274f74328af3ee9, and f77b51bcee7be2bb686b5f7a2d4a1921e4bdb9f4. These patches add kfree_skb() to the missing error path for consistency, remove redundant frees in affected drivers to prevent double-free, and update the function's kdoc to document skb ownership guarantees.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-18688
Vulnerability details
In the Linux kernel, the following vulnerability has been resolved: wifi: mac80211: always free skb on ieee80211_tx_prepare_skb() failure ieee80211_tx_prepare_skb() has three error paths, but only two of them free the skb. The first error path (ieee80211_tx_prepare() returning TX_DROP) does not…
more
free it, while invoke_tx_handlers() failure and the fragmentation check both do. Add kfree_skb() to the first error path so all three are consistent, and remove the now-redundant frees in callers (ath9k, mt76, mac80211_hwsim) to avoid double-free. Document the skb ownership guarantee in the function's kdoc.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
Local kernel memory corruption vulnerability in mac80211 enables privilege escalation via exploitation of the skb handling flaw.
CVEs Like This One
Affected Assets
Mitigating Controls
Mitigating Controls (NIST 800-53 r5) AI
Directly mandates timely remediation of software flaws like the inconsistent skb freeing in ieee80211_tx_prepare_skb() that causes the memory leak.
Requires vulnerability scanning to identify systems running vulnerable Linux kernel versions affected by CVE-2026-23444.
Ensures receipt and dissemination of security alerts and directives about kernel vulnerabilities like CVE-2026-23444 to enable patching.