Use-after-free of orphaned AF_UNIX in Ubuntu builds of Linux kernel
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- Fix
- Fixed in 6.8.0-84.84
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: total
Summary
Ubuntu Linux 6.8 GA retains the legacy AF_UNIX garbage collector but backports upstream commit 8594d9b85c07 ("af_unix: Don’t call skb_get() for OOB skb"). When orphaned MSG_OOB sockets hit unix_gc(), the garbage collector still calls kfree_skb() as if OOB SKBs held two references; on Ubuntu Linux 6.8 (Noble Numbat) kernel tree, they have only the queue reference, so the buffer is freed while still reachable and subsequent queue walks dereference freed memory, yielding a reliable local privilege escalation (LPE) caused by a use-after-free (UAF). Ubuntu builds that have already taken the new GC stack from commit 4090fa373f0e, and mainline Linux kernels shipping that infrastructure are unaffected because they no longer execute the legacy collector path. This issue affects Ubuntu Linux from 6.8.0-56.58 before 6.8.0-84.84.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: total
- Record last updated
Affected versions
- linux
From 6.8.0-56.58 · fixed in 6.8.0-84.84