CVE-2026-72237 perf/x86/amd/brs: Fix kernel address leakage
Local attackers can leak kernel memory addresses via AMD BRS branch records, bypassing user-space filtering restrictions.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-72237?
CVE-2026-72237 is a vulnerability in Linux, published on 15 Aug 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
In the Linux kernel, the following vulnerability has been resolved:
perf/x86/amd/brs: Fix kernel address leakage
A user-only branch stack can contain branches that originate from the kernel. As a result, kernel addresses are exposed to user space even when PERF_SAMPLE_BRANCH_USER is requested. On AMD processors supporting X86_FEATURE_BRS (Zen 3 only), perf can still report entries such as SYSRET/interrupt returns for which the branch-from addresses are in the kernel.
E.g.
$ perf record -j any,u -c 4000 -e branch-brs -o - -- \ perf bench syscall basic --loop 1000 | \ perf script -i - -F brstack|tr ' ' '\n'| \ grep -E '0x[89a-f][0-9a-f]{15}'
... 0xffffffff810001c4/0x72e2e32955eb/-/-/-/0//- 0xffffffff810001c4/0x72e2d94a9821/-/-/-/0//- 0xffffffff810001c4/0x72e2d94ffa1b/-/-/-/0//- ...
BRS provides no hardware branch filtering, so privilege level filtering is performed entirely in software. However, amd_brs_match_plm() only validates the branch-to address against the requested privilege levels. For branches from the kernel to user space, the branch-from address is left unchecked and is leaked. Extend the software filter to also validate the branch-from address, so that any branch record whose branch-from address is in the kernel is dropped when PERF_SAMPLE_BRANCH_USER is requested.
Which versions are affected by CVE-2026-72237?
How do I fix CVE-2026-72237?
Apply the vendor's patch.
Is CVE-2026-72237 being exploited?
There is no known exploitation of CVE-2026-72237 in the wild and no public exploit code.
Sources
Also known as BELL-CVE-2026-72237, DEBIAN-CVE-2026-72237, GHSA-wcfv-p978-69xf, UBUNTU-CVE-2026-72237.