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.
References6
- git.kernel.org/stable/c/31d6e6c0ba8d5a7bd59660035a089307100c5e8e
- git.kernel.org/stable/c/374775626c327aec2425c16b4d36706e5f8718b8
- git.kernel.org/stable/c/5488d3a69d205e28f74f18857b853aa12e778e66
- git.kernel.org/stable/c/84d4d2a6988c9a733f7821452cefb5b0d93de2d1
- git.kernel.org/stable/c/dc662eed1c432cc2fd4e9314f58d30b3a8cca7cc
- git.kernel.org/stable/c/f7990c2b0f08b8841fcd2652d1d7002f5994a7a7
Metrics
- CVSS 3.1
-
9.8
CRITICAL
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - EPSS — exploit probability
- 1% percentile: 57 · as of 11 November 2026
- CWE
- CWE-787
Could this be exploited in your environment?
A patch closes the known hole. A penetration test shows what an attacker can still reach — with proof.