# CVE-2026-63090: proftpd-dfsg: ProFTPD before 1.3.9c and 1.3.10rc3 contains a heap-based buffer overflow vulnerability in the mod_sftp module that a...

CVE-2026-63090 is fixed in proftpd-dfsg on 1 platform, first by DEBIAN-CVE-2026-63090, released July 21, 2026. It is not reported as exploited. Patch Radar priority: Routine.

- Web page: https://patchblox.com/security/cve/CVE-2026-63090
- Priority: Routine
- CVSS: n/a
- EPSS: 0.0093
- CISA KEV: not listed
- Exploited (vendor report): no
- Publicly disclosed: no
- Published: Jul 20, 2026

## Description

ProFTPD before 1.3.9c and 1.3.10rc3 contains a heap-based buffer overflow vulnerability in the mod_sftp module that allows authenticated low-privilege attackers to achieve arbitrary code execution by sending crafted SFTP packet fragments exceeding the 16 KB reassembly buffer in the fxp.c component. Attackers can supply oversized fragments to trigger an incorrectly conditioned reallocation, corrupt pool freelist metadata, overwrite the root_fs BSS global pointer to reference a fake filesystem struct, and redirect pr_fsio_stat() to system() via a crafted RENAME request.

## Where it's fixed

| Platform | Product | Fixed in | Fix | Released |
|---|---|---|---|---|
| Linux | proftpd-dfsg Debian 13.5 (trixie) | 1.3.8.c+dfsg-4+deb13u3 | [DEBIAN-CVE-2026-63090](https://patchblox.com/security/data/fix/linux/debian-cve-2026-63090.md) | Jul 21, 2026 |
| Linux | proftpd-dfsg Debian 14 | 1.3.9c~dfsg-1 | [DEBIAN-CVE-2026-63090](https://patchblox.com/security/data/fix/linux/debian-cve-2026-63090.md) | Jul 21, 2026 |

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Data as of 2026-11-09T01:18:40Z 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 Patchblox finds out-of-date software on Windows, macOS and Linux and updates it through release rings: https://patchblox.com/demo

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