CVE-2026-77375: SFTPGo Denial of Service Vulnerability

MODERATE
Advisory Identifier: GHSA-q7pc-356p-hggc
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CVSS 6.5
CWE-129
Published
Advisory Summary

CVE-2026-77375 is a MODERATE (CVSS 6.5) denial of service vulnerability (CWE-129: Improper Validation of Array Index) affecting SFTPGo libraries in the Go ecosystem. The issue involves denial of service via malformed ssh channel request. Remediation is available by upgrading affected packages to version 2.7.5.

CVE-2026-77375 at a Glance

CVE Identifier CVE-2026-77375
GHSA Identifier GHSA-q7pc-356p-hggc
Severity MODERATE
CVSS v3.1 Base Score 6.5
CWE Classification CWE-129: Improper Validation of Array Index
Affected Product SFTPGo
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 6.5

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality None (C:N)
Integrity None (I:N)
Availability High (A:H)

How to Fix CVE-2026-77375

To remediate this vulnerability, upgrade all affected SFTPGo dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/drakkan/sftpgo/v2 fixed: 2.7.5 
Upgrade github.com/drakkan/sftpgo/v2 to 2.7.5
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/drakkan/sftpgo/v2

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-77375, inspect your project dependencies for SFTPGo:

inspect dependencies for github.com/drakkan/sftpgo/v2

Analyze the terminal output to locate any version of SFTPGo in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 2.7.5), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-129: Improper Validation of Array Index, where the product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array. In SFTPGo, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

### Summary A flaw in the SSH service allows an authenticated client to crash the server by sending a malformed protocol message while opening a channel. ### Impact Any user able to authenticate over SSH can trigger an unhandled error condition that aborts the server process. This results in a denial of service affecting all connected users until the service is restarted. No confidentiality or integrity impact has been identified; the issue is limited to availability.

CVE-2026-77375 Affected SFTPGo Versions

1 component(s)
Fixed Versions:
2.7.5
Product / Package Ecosystem Affected Versions Fixed Version
github.com/drakkan/sftpgo/v2
golang/github.com/drakkan/sftpgo/v2
Go
< 2.7.5
2.7.5

References

GitHub Advisory / Wiki ADVISORY
https://github.com/drakkan/sftpgo/security/advisories/GHSA-q7pc-356p-hggc
NVD — CVE-2026-77375 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-77375
Security Fix Commit FIX COMMIT
https://github.com/drakkan/sftpgo/commit/4f751232d7025cf2f7360e01ee8dca81e74b48b0
SFTPGo Source Repository REPOSITORY
https://github.com/drakkan/sftpgo
SFTPGo Release RELEASE
https://github.com/drakkan/sftpgo/releases/tag/v2.7.5

Frequently Asked Questions

What is CVE-2026-77375?
CVE-2026-77375 is a security vulnerability in SFTPGo involving Denial of service via malformed SSH channel request under CWE-129: Improper Validation of Array Index.
Which SFTPGo versions are affected?
Affected versions include releases prior to 2.7.5 across affected packages: github.com/drakkan/sftpgo/v2.
What version fixes CVE-2026-77375?
Upgrading to 2.7.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/drakkan/sftpgo/v2 affected?
Yes, github.com/drakkan/sftpgo/v2 is affected in releases prior to 2.7.5. Upgrade your dependency to 2.7.5 or later.
What is the CVSS score of CVE-2026-77375?
CVE-2026-77375 has a CVSS v3.1 base score of 6.5 (MODERATE) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H.
What CWE is associated with CVE-2026-77375?
CVE-2026-77375 is classified under CWE-129: Improper Validation of Array Index (The product uses untrusted input when calculating or using an array index, but the product does not validate or incorrectly validates the index to ensure the index references a valid position within the array.).
How can I check Go dependencies for CVE-2026-77375?
Run the dependency tree command: 'inspect dependencies for github.com/drakkan/sftpgo/v2'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-q7pc-356p-hggc",
  "modified" : "2026-10-15T20:14:20Z",
  "published" : "2026-10-15T20:14:20Z",
  "aliases" : [ "CVE-2026-77375" ],
  "summary" : "SFTPGo: Denial of service via malformed SSH channel request",
  "details" : "### Summary\n\nA flaw in the SSH service allows an authenticated client to crash the server by sending a malformed protocol message while opening a channel.\n\n### Impact\n\nAny user able to authenticate over SSH can trigger an unhandled error condition that aborts the server process. This results in a denial of service affecting all connected users until the service is restarted. No confidentiality or integrity impact has been identified; the issue is limited to availability.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/drakkan/sftpgo/v2"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "2.7.5"
      } ]
    } ],
    "database_specific" : {
      "last_known_affected_version_range" : "<= 2.7.4"
    }
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/drakkan/sftpgo/security/advisories/GHSA-q7pc-356p-hggc"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-77375"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/drakkan/sftpgo/commit/4f751232d7025cf2f7360e01ee8dca81e74b48b0"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/drakkan/sftpgo"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/drakkan/sftpgo/releases/tag/v2.7.5"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-129" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-10-15T20:14:20Z",
    "nvd_published_at" : "2026-10-13T15:17:49Z"
  }
}