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.
CVSS Details
- CVSS 4.0 Base Score: 7.1 (HIGH)
- CVSS 4.0 Vector: (CVSS:4.0/AV:L/AC:H/AT:N/PR:L/UI:N/VC:N/VI:H/VA:L/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X)
Covered by Rapid7
| Product | Vendor Advisory | Solution File | Added | Published |
|---|---|---|---|---|
| Ubuntu | — | Upgrade linux-raspiUpgrade linux-realtimeUpgrade linux-nvidia-lowlatencyUpgrade linux-azure-nvidiaUpgrade linux-nvidia-6.8Upgrade linux-xilinxUpgrade linux-ibmUpgrade linux-raspi-realtimeUpgrade linux-oracleUpgrade linux-nvidiaUpgrade linux-azureUpgrade linux-oracle-6.8Upgrade linux-ibm-6.8Upgrade linux-fipsUpgrade linux-riscv-6.8Upgrade linux-gcp-fipsUpgrade linux-aws-6.8Upgrade linux-hwe-6.8Upgrade linux-nvidia-tegraUpgrade linux-gcpUpgrade linuxUpgrade linux-gcp-6.8Upgrade linux-aws-fipsUpgrade linux-lowlatencyUpgrade linux-azure-fipsUpgrade linux-realtime-6.8Upgrade linux-awsUpgrade linux-gkeUpgrade linux-gkeopUpgrade linux-azure-6.8Upgrade linux-lowlatency-hwe-6.8 | Mar 9, 2026 | Mar 6, 2026 |
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