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

Q: How do I fix CVE-2026-63090?

proftpd: upgrade to 1.3.9c. Exact commands for each OS are on this page.

Q: Is CVE-2026-63090 being exploited?

CVE-2026-63090 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-63090 affect?

CVE-2026-63090 affects proftpd. Severity is high (CVSS 8.8). 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 ex

This month

HIGH 8.8UPGRADE

CVE-2026-63090 is a high-severity flaw (CVSS 8.8) affecting proftpd. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

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

Why this priority

High severity

A fixed release or distro patch exists.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	None
EPSS exploit chance	0.9% (top 40%)
CISA exploited list	No
Weakness	CWE-122
Published	2026-07-20
Last modified	2026-07-30

Publisher (CNA): VulnCheck · Vendor: proftpd

Last updated 2026-07-30 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-07-20 15:16 UTCPublished CVE record published
2026-07-30 17:19 UTCUpdated Record last modified

proftpd proftpd UPGRADE

Affected: < 1.3.9c · 1.3.10 rc1 · 1.3.10 rc2

Fixed in: 1.3.9c

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy proftpd || rpm -q proftpd || proftpd --version

2. UPGRADE to 1.3.9c (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade proftpd

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade proftpd

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-63090?

proftpd: upgrade to 1.3.9c. Exact commands for each OS are on this page.

Is CVE-2026-63090 being exploited?

CVE-2026-63090 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-63090 affect?

CVE-2026-63090 affects proftpd. Severity is high (CVSS 8.8). 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 ex

How urgent is CVE-2026-63090?

Priority 46/100. High severity

Software pages

ProFTPD vulnerabilities

Related CVEs

CVE-2026-35025 HIGH 8.1 UPGRADE ProFTPD through 1.3.9b and 1.3.10rc2 contains an access control bypass vulnerability that allows authenticated
CVE-2026-53994 HIGH 7.5 UPGRADE ProFTPD mod_sftp contains a heap-based buffer overflow reachable by an authenticated SFTP user
CVE-2015-3306 CRITICAL 10.0 EXPLOITED MITIGATE MITIGATE ProFTPD Improper Access Control Vulnerability
CVE-2026-63091 MEDIUM 6.5 UPGRADE ProFTPD before 1.3.9c and 1.3.10rc3 contains a signed integer overflow vulnerability in the mod_sftp module's

References

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