CVE-2026-3497Network attack vector

Pre-auth crash and code execution via uninitialized token

Published Mar 12, 2026 · Updated Mar 12, 2026

Uninitialized memory use in Ubuntu OpenSSH GSSAPI patches allows remote attackers to crash sshd or execute code before authentication. In the GSSAPI key-exchange server loop, sshpkt_disconnect() returns on an unexpected message, leaving recv_tok uninitialized before IPC and gss_release_buffer() frees its garbage pointer. The affected delta is absent from upstream OpenSSH, and exposure requires the non-default GSSAPIKeyExchange setting; compiler hardening determines whether the result is a child crash or code execution.

CVSS severity6.9
Medium
EPSS probability2.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Uninitialized memory use in Ubuntu OpenSSH GSSAPI patches allows remote attackers to crash sshd or execute code before authentication. In the GSSAPI key-exchange server loop, sshpkt_disconnect() returns on an unexpected message, leaving recv_tok uninitialized before IPC and gss_release_buffer() frees its garbage pointer. The affected delta is absent from upstream OpenSSH, and exposure requires the non-default GSSAPIKeyExchange setting; compiler hardening determines whether the result is a child crash or code execution.

The record

CVE
CVE-2026-3497
Published
Mar 12, 2026
Updated
Mar 12, 2026
Vendor
OpenBSD Project
Product
OpenSSH
Classifications
CWE-908, T1499.004
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Mar 12, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 12, 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=1:10.0p1-5ubuntu5 <1:10.0p1-5ubuntu5.1
  2. Affected versionversion=1:8.9p1-3 <1:8.9p1-3ubuntu0.14
  3. Affected versionversion=1:9.6p1-3ubuntu13 <1:9.6p1-3ubuntu13.15

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

OpenBSD Project · OpenSSHversion=1:10.0p1-5ubuntu5 <1:10.0p1-5ubuntu5.1; version=1:8.9p1-3 <1:8.9p1-3ubuntu0.14; version=1:9.6p1-3ubuntu13 <1:9.6p1-3ubuntu13.15

Published CVSS scores

8.2Canonical Ltd.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H
6.9Canonical Ltd.CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-908Use of Uninitialized Resource
T1499.004Application or System Exploitation

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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