dm-verity: fix buffer overflow in FEC calculation (CVE-2026-72098) | HOL Guard CVE

Critical · CVSS 9.8CVE-2026-72098

dm-verity: fix buffer overflow in FEC calculation

Answer in brief

CVE-2026-72098 records a Critical severity (CVSS 9.8) vulnerability in dm-verity: fix buffer overflow in FEC calculation. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Aug 15, 2026Updated Aug 17, 2026Source checked Sep 29, 2026First seen by HOL Aug 15, 2026Material review Aug 17, 2026

Upstream Advisory

Key facts

Risk: Critical · CVSS 9.8
Exploitation: Not marked as known exploited
Affected software: 2 mapped packages or products
Fix availability: Available

Why this deserves its current priority

CVSS is 9.8. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
Linux/Linuxgeneric	>=a739ff3f543afbb4a041c16cd0182c8e8d366e70 <5488d3a69d205e28f74f18857b853aa12e778e66 \|\| >=a739ff3f543afbb4a041c16cd0182c8e8d366e70 <f7990c2b0f08b8841fcd2652d1d7002f5994a7a7 \|\| >=a739ff3f543afbb4a041c16cd0182c8e8d366e70 <31d6e6c0ba8d5a7bd59660035a089307100c5e8e	5488d3a69d205e28f74f18857b853aa12e778e66, f7990c2b0f08b8841fcd2652d1d7002f5994a7a7, 31d6e6c0ba8d5a7bd59660035a089307100c5e8e
Linux/Linuxgeneric	4.5	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for Linux/Linux, Linux/Linux.
Review the reported fix. Update Linux/Linux to 5488d3a69d205e28f74f18857b853aa12e778e66 if you use the affected versions. Test the change in a non-production environment first.

Evidence timeline and material changes

Published upstream
Aug 15, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Aug 17, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Aug 15, 2026

Sources and claim methodology

Upstream source description

In the Linux kernel, the following vulnerability has been resolved: dm-verity: fix buffer overflow in FEC calculation There's a buffer overflow in dm-verity-fec: if (neras && *neras <= v->fec->roots) fio->erasures[(*neras)++] = i; This allows *neras to reach roots + 1 (the post-increment pushes it past roots). This value is then passed as no_eras to decode_rs8(). Inside the RS decoder (lib/reed_solomon/decode_rs.c:113-121), the erasure locator polynomial loop writes lambda[j] where j can reach nroots + 1 — one element past the end of lambda[] (which is sized nroots + 1, valid indices 0..nroots). The out-of-bounds write lands on syn[0], corrupting the syndrome buffer.

Quoted source text, attributed separately from HOL analysis.