# CVE-2026-97587: perf: RISC-V: store available counter mask as bitmap

CVE-2026-97587 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-97587, released September 29, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-97587
- Priority: Routine
- CVSS: 5.5 (Moderate)
- EPSS: 0.0021
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 25, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-97587

## Description

In the Linux kernel, the following vulnerability has been resolved:  perf: RISC-V: store available counter mask as bitmap  The available-counter mask was a single unsigned long, but iteration uses RISCV_MAX_COUNTERS, which is 64. On RV32 that reads past the object. Filling with an unsigned-long bit at index 32 and above is also wrong.  Use DECLARE_BITMAP and set_bit/bitmap helpers. Walk each bitmap word into CFG_MATCH when checking events, when allocating an index, and when stopping all counters. Set the counter base to i times BITS_PER_LONG. Share the CFG_MATCH ecall through a small helper so the 32-bit argument split is not duplicated. On qemu-system-riscv32 the probe bitmap has bits above XLEN set, so the first word alone is not enough.  [pjw@kernel.org: updated to apply; fixed checkpatch.pl issues]

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.111-1 | [DEBIAN-CVE-2026-97587](https://patchblox.com/security/data/fix/linux/debian-cve-2026-97587.md) | Sep 29, 2026 |
| Linux | linux Debian 14 | 7.2.7-1 | [DEBIAN-CVE-2026-97587](https://patchblox.com/security/data/fix/linux/debian-cve-2026-97587.md) | Sep 29, 2026 |
| Linux | linux-6.12 Debian 12.15 (bookworm) | 6.12.111-1~deb12u1 | [DEBIAN-CVE-2026-97587](https://patchblox.com/security/data/fix/linux/debian-cve-2026-97587.md) | Sep 29, 2026 |

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Data as of 2026-11-08T00:53:09Z UTC. Source: Patchblox Patch Radar (https://patchblox.com/security/patch-radar). Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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