# CVE-2026-99135: dm-integrity: fix infinite loop on discard with large tag size

CVE-2026-99135 is fixed in linux on 1 platform, first by DEBIAN-CVE-2026-99135, released November 3, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-99135
- Priority: Routine
- CVSS: 5.5 (Moderate)
- EPSS: 0.0019
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Oct 28, 2026
- Vendor advisory: https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-99135

## Description

In the Linux kernel, the following vulnerability has been resolved:  dm-integrity: fix infinite loop on discard with large tag size  When integrity_metadata handles a discard, it fills a buffer with DISCARD_FILLER and writes it over the tags, max_blocks blocks at a time. If the kmalloc fails, the buffer is the on-stack array checksums_onstack and max_size is set to HASH_MAX_DIGESTSIZE. So if the tag size is larger than HASH_MAX_DIGESTSIZE, max_blocks is zero, bi_size is never decremented and the loop never terminates.  Fix this by using sizeof(checksums_onstack) as max_size. The array has MAX_TAG_SIZE bytes since commit b93b6643e9b5 ("dm integrity: fix a crash with unusually large tag size"), so max_blocks is at least 1.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 13.5 (trixie) | 6.12.115-2 | [DEBIAN-CVE-2026-99135](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99135.md) | Nov 3, 2026 |
| Linux | linux Debian 14 | 7.2.13-1 | [DEBIAN-CVE-2026-99135](https://patchblox.com/security/data/fix/linux/debian-cve-2026-99135.md) | Nov 3, 2026 |

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Data as of 2026-11-08T13:06:02Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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