# CVE-2025-40241: linux: In the Linux kernel, the following vulnerability has been resolved:  erofs: fix crafted invalid cases for encoded ext...

CVE-2025-40241 is fixed in linux on 1 platform by DEBIAN-CVE-2025-40241 (version 6.17.6-1), released December 4, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-40241
- Priority: High
- CVSS: 7.8 (high)
- EPSS: 0.0015
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Dec 4, 2025

## Description

In the Linux kernel, the following vulnerability has been resolved:  erofs: fix crafted invalid cases for encoded extents  Robert recently reported two corrupted images that can cause system crashes, which are related to the new encoded extents introduced in Linux 6.15:    - The first one [1] has plen != 0 (e.g. plen == 0x2000000) but     (plen & Z_EROFS_EXTENT_PLEN_MASK) == 0. It is used to represent     special extents such as sparse extents (!EROFS_MAP_MAPPED), but     previously only plen == 0 was handled;    - The second one [2] has pa 0xffffffffffdcffed and plen 0xb4000,     then "cur [0xfffffffffffff000] += bvec.bv_len [0x1000]" in     "} while ((cur += bvec.bv_len) < end);" wraps around, causing an     out-of-bound access of pcl->compressed_bvecs[] in     z_erofs_submit_queue().  EROFS only supports 48-bit physical block     addresses (up to 1EiB for 4k blocks), so add a sanity check to     enforce this.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | linux Debian 14 | 6.17.6-1 | [DEBIAN-CVE-2025-40241](https://patchblox.com/security/data/fix/linux/debian-cve-2025-40241.md) | Dec 4, 2025 |

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