CVE-2026-63090Network attack vector

Authenticated code execution via SFTP packet reassembly

Published Jul 20, 2026 · Updated Jul 20, 2026

Heap-based buffer overflow in ProFTPD mod_sftp before 1.3.9c and 1.3.10rc3 allows remote authenticated users to execute code. The fxp_packet_add_cache_data path computes a larger size after fragmented SFTP data exceeds its 16 KB buffer, but reallocates only under an unrelated pool threshold before appending out of bounds. Low-privilege SFTP credentials and mod_sftp exposure are required; successful corruption permits execution in the ProFTPD process context.

CVSS severity8.7
High
EPSS probability0.93%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Heap-based buffer overflow in ProFTPD mod_sftp before 1.3.9c and 1.3.10rc3 allows remote authenticated users to execute code. The fxp_packet_add_cache_data path computes a larger size after fragmented SFTP data exceeds its 16 KB buffer, but reallocates only under an unrelated pool threshold before appending out of bounds. Low-privilege SFTP credentials and mod_sftp exposure are required; successful corruption permits execution in the ProFTPD process context.

The record

CVE
CVE-2026-63090
Published
Jul 20, 2026
Updated
Jul 20, 2026
Vendor
ProFTPD Project
Product
ProFTPD
Classifications
CWE-122, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jul 20, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <1.3.9c
  2. Affected versionversion=1.3.10rc1 <1.3.10rc3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

ProFTPD Project · ProFTPDversion=0 <1.3.9c; version=1.3.10rc1 <1.3.10rc3

Published CVSS scores

8.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-122Heap-based Buffer Overflow
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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