CVE-2026-72237

NameCVE-2026-72237
DescriptionIn 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
linux (PTS)bookworm6.1.176-1vulnerable
bookworm (security)6.1.180-1vulnerable
trixie6.12.94-1vulnerable
trixie (security)6.12.107-1fixed
forky7.1.12-1fixed
sid7.1.13-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
linuxsourcebullseye(not affected)
linuxsourcetrixie6.12.100-1
linuxsource(unstable)7.1.5-1

Notes

[bullseye] - linux <not-affected> (Vulnerable code not present)
https://git.kernel.org/linus/47915e855fb38b42133e31ba917d99565f862154 (7.2-rc3)

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