# CVE-2025-57632: libsmb2: libsmb2 6.2+ is vulnerable to Buffer Overflow

CVE-2025-57632 is fixed in libsmb2 on 1 platform, first by DEBIAN-CVE-2025-57632, released September 25, 2025. It is not reported as exploited. Patch Radar priority: High.

- Web page: https://patchblox.com/security/cve/CVE-2025-57632
- Priority: High
- CVSS: 7.5 (high)
- EPSS: 0.0058
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Sep 25, 2025

## Description

libsmb2 6.2+ is vulnerable to Buffer Overflow. When processing SMB2 chained PDUs (NextCommand), libsmb2 repeatedly calls smb2_add_iovector() to append to a fixed-size iovec array without checking the upper bound of v->niov (SMB2_MAX_VECTORS=256). An attacker can craft responses with many chained PDUs to overflow v->niov and perform heap out-of-bounds writes, causing memory corruption, crashes, and potentially arbitrary code execution. The SMB2_OPLOCK_BREAK path bypasses message ID validation.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | libsmb2 Debian 13.5 (trixie) | 6.2+dfsg-2+deb13u1 | [DEBIAN-CVE-2025-57632](https://patchblox.com/security/data/fix/linux/debian-cve-2025-57632.md) | Sep 25, 2025 |
| Linux | libsmb2 Debian 14 | 6.2+dfsg-3 | [DEBIAN-CVE-2025-57632](https://patchblox.com/security/data/fix/linux/debian-cve-2025-57632.md) | Sep 25, 2025 |

---

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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

Free to use with attribution: show "Data: Patchblox Patch Radar" with a link to https://patchblox.com/security/patch-radar. Terms, including what needs a written agreement: https://patchblox.com/security/patch-radar/use-the-data

Product names, logos and trademarks shown on Patch Radar belong to their respective owners. They are used only to identify the software each security fix applies to and to help readers find their platform. Their use does not imply any affiliation with, or endorsement by, those owners, and Patchblox is not affiliated with any of them.