CVE-2026-90393 Affecting linux-6.12 package, versions <6.12.111-1~deb12u1
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-DEBIAN12-LINUX612-20507241
- published5 Oct 2026
- disclosed17 Sept 2026
Introduced: 17 Sep 2026
NewCVE-2026-90393 (opens in a new tab)How to fix?
Upgrade Debian:12 linux-6.12 to version 6.12.111-1~deb12u1 or higher.
NVD Description
Note: Versions mentioned in the description apply only to the upstream linux-6.12 package and not the linux-6.12 package as distributed by Debian.
See How to fix? for Debian:12 relevant fixed versions and status.
In the Linux kernel, the following vulnerability has been resolved:
bpf: Fix potential UAF in bpf_netns_link_update_prog
In bpf_netns_link_update_prog, the checks for old_prog and prog type are currently performed locklessly before acquiring netns_bpf_mutex. This creates a race condition that can lead to a UAF issue.
If two threads concurrently execute BPF_LINK_UPDATE on the same netns link, the following execution path can trigger a UAF:
CPU0 CPU1 bpf_netns_link_update_prog if (old_prog && old_prog != link->prog) return -EPERM; bpf_netns_link_update_prog if (old_prog && old_prog != link->prog) ... old_prog = xchg(&link->prog, new_prog); bpf_prog_put(old_prog); if (new_prog->type != link->prog->type) <-- trigger UAF
Fix this by moving the old_prog and prog->type checks inside the netns_bpf_mutex critical section. Meanwhile, use guard() to simplify lock management and avoid all the goto jumping.
References
- https://security-tracker.debian.org/tracker/CVE-2026-90393
- https://git.kernel.org/stable/c/277168cb9d153ce8e9c3f9275670e32ae61b41d6
- https://git.kernel.org/stable/c/5c5997836381010fc5907b36bc17d3b19407e933
- https://git.kernel.org/stable/c/79a66fd997d4eecf17302d613194879eb32e0986
- https://git.kernel.org/stable/c/923f559e95b89b33c7e1793b3d8f7f4ec9b2e4b7
- https://git.kernel.org/stable/c/bda86e9f31b9a296b6e64a51c91dc776fc9f613e
- https://git.kernel.org/stable/c/bdddf3e1493ee973619c154a57071ce67f78598b
- https://git.kernel.org/stable/c/d462b5481d77ce7df8a5ff89a699386f00c9214d
- https://git.kernel.org/stable/c/f4ce6803df4095777191d800bebc50219b615ca0