Skip to main content
Threat Radar animated logo
DashboardThreatsMapFeedsPricingView Plans & Pricing
reconnecting
Press slash or control plus K to focus the search. Use the arrow keys to navigate results and press enter to open a threat.
Reconnecting to live updates…
EPSS 0.6%top 54%

In MIT Kerberos 5 (aka krb5) before 1.22.3, there is a NULL pointer dereference if an application calls gss_accept_sec_context() on a system with a…

0
Medium
VulnerabilityCVE-2026-40355gcveosvubuntu-cve-2026-40355ubuntu-pro-14-04-ltsubuntu-pro-16-04-ltsubuntu-pro-18-04-ltsubuntu-20-04-ltsubuntu-22-04-ltsubuntu-24-04-ltsubuntu-25-10ubuntu-26-04-lts
Published: 04/28/2026 (04/28/2026, 06:16:00 UTC)
Source: GCVE Database
Product: krb5

Description

MIT Kerberos 5 (krb5) versions before 1.22.3 contain a vulnerability where calling gss_accept_sec_context() on a system with a NegoEx mechanism registered in /etc/gss/mech can cause a NULL pointer dereference. This can be triggered by an unauthenticated remote attacker, leading to process termination in parse_nego_message.

CVSS v3.1

Score 5.9medium

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected software

Ubuntu:Pro:14.04:LTSmore threats →ghsa
krb5
pkg:deb/ubuntu/[email protected]+dfsg-2ubuntu5.4+esm7?arch=source&distro=esm-infra-legacy/trusty
Affected versions
=1.10.1+dfsg-6.1ubuntu1=1.11.3+dfsg-3ubuntu2=1.12+dfsg-2ubuntu1=1.12+dfsg-2ubuntu2=1.12+dfsg-2ubuntu3=1.12+dfsg-2ubuntu4=1.12+dfsg-2ubuntu4.2=1.12+dfsg-2ubuntu5=1.12+dfsg-2ubuntu5.1=1.12+dfsg-2ubuntu5.2=1.12+dfsg-2ubuntu5.3=1.12+dfsg-2ubuntu5.4=1.12+dfsg-2ubuntu5.4+esm1=1.12+dfsg-2ubuntu5.4+esm2=1.12+dfsg-2ubuntu5.4+esm3=1.12+dfsg-2ubuntu5.4+esm4=1.12+dfsg-2ubuntu5.4+esm5=1.12+dfsg-2ubuntu5.4+esm6=1.12+dfsg-2ubuntu5.4+esm7
Ubuntu:Pro:16.04:LTSmore threats →ghsa
krb5
pkg:deb/ubuntu/[email protected]+dfsg-5ubuntu2.2+esm7?arch=source&distro=esm-infra/xenial
Affected versions
=1.13.2+dfsg-2=1.13.2+dfsg-3=1.13.2+dfsg-4=1.13.2+dfsg-5=1.13.2+dfsg-5ubuntu1=1.13.2+dfsg-5ubuntu2=1.13.2+dfsg-5ubuntu2.1=1.13.2+dfsg-5ubuntu2.1+esm1=1.13.2+dfsg-5ubuntu2.2=1.13.2+dfsg-5ubuntu2.2+esm1=1.13.2+dfsg-5ubuntu2.2+esm2=1.13.2+dfsg-5ubuntu2.2+esm3=1.13.2+dfsg-5ubuntu2.2+esm4=1.13.2+dfsg-5ubuntu2.2+esm5=1.13.2+dfsg-5ubuntu2.2+esm6=1.13.2+dfsg-5ubuntu2.2+esm7
Ubuntu:Pro:18.04:LTSmore threats →ghsa
krb5
pkg:deb/ubuntu/[email protected]+esm5?arch=source&distro=esm-infra/bionic
Affected versions
=1.15.1-2=1.16-2=1.16-2build1=1.16-2ubuntu0.1=1.16-2ubuntu0.1+esm1=1.16-2ubuntu0.2=1.16-2ubuntu0.3=1.16-2ubuntu0.4=1.16-2ubuntu0.4+esm1=1.16-2ubuntu0.4+esm2=1.16-2ubuntu0.4+esm3=1.16-2ubuntu0.4+esm5
Ubuntu:20.04:LTSmore threats →ghsa
krb5
pkg:deb/ubuntu/[email protected]?arch=source&distro=focal
Affected versions
=1.17-6=1.17-6ubuntu3=1.17-6ubuntu4=1.17-6ubuntu4.1=1.17-6ubuntu4.2=1.17-6ubuntu4.3=1.17-6ubuntu4.4=1.17-6ubuntu4.6=1.17-6ubuntu4.7=1.17-6ubuntu4.8=1.17-6ubuntu4.9=1.17-6ubuntu4.11
Ubuntu:22.04:LTSmore threats →ghsa
krb5
pkg:deb/ubuntu/[email protected]?arch=source&distro=jammy
Affected versions
<1.19.2-2ubuntu0.8=1.18.3-6=1.18.3-7=1.19.2-0ubuntu1=1.19.2-1=1.19.2-2=1.19.2-2ubuntu0.1=1.19.2-2ubuntu0.2=1.19.2-2ubuntu0.3=1.19.2-2ubuntu0.4=1.19.2-2ubuntu0.5=1.19.2-2ubuntu0.6=1.19.2-2ubuntu0.7
Ubuntu:24.04:LTSmore threats →ghsa
krb5
pkg:deb/ubuntu/[email protected]?arch=source&distro=noble
Affected versions
<1.20.1-6ubuntu2.7=1.20.1-3ubuntu1=1.20.1-5build1=1.20.1-6ubuntu1=1.20.1-6ubuntu2=1.20.1-6ubuntu2.1=1.20.1-6ubuntu2.2=1.20.1-6ubuntu2.3=1.20.1-6ubuntu2.4=1.20.1-6ubuntu2.5=1.20.1-6ubuntu2.6
Ubuntu:25.10more threats →ghsa
krb5
pkg:deb/ubuntu/[email protected]?arch=source&distro=questing
Affected versions
=1.21.3-4ubuntu2=1.21.3-5ubuntu1=1.21.3-5ubuntu2
Ubuntu:26.04:LTSmore threats →ghsa
krb5
pkg:deb/ubuntu/[email protected]?arch=source&distro=resolute
Affected versions
<1.22.1-2ubuntu4.1=1.21.3-5ubuntu2=1.22.1-2=1.22.1-2ubuntu2=1.22.1-2ubuntu3=1.22.1-2ubuntu4

Run on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.

AI-Powered Analysis

Machine-generated threat intelligence

AILast updated: 07/22/2026, 23:52:09 UTC

Technical Analysis

In MIT Kerberos 5 (krb5) prior to version 1.22.3, a NULL pointer dereference vulnerability exists when an application invokes gss_accept_sec_context() on systems that have a NegoEx mechanism registered in /etc/gss/mech. An unauthenticated remote attacker can exploit this by sending crafted input that triggers the NULL pointer dereference, causing the affected process to crash during the parse_nego_message function execution.

Potential Impact

The vulnerability allows an unauthenticated remote attacker to cause a denial of service by crashing the process using the gss_accept_sec_context() function. There is no indication of confidentiality, integrity, or authentication compromise. The impact is limited to availability disruption due to process termination.

Mitigation Recommendations

A fix is available in MIT Kerberos 5 version 1.22.3 and later. Users should upgrade to version 1.22.3 or newer to remediate this vulnerability. Patch status is confirmed by the version boundary provided. No vendor advisory content contradicts this remediation.

Pro Console: star threats, build custom feeds, automate alerts via Slack, email & webhooks.Upgrade to Pro

Technical Details

Gcve Source
db.gcve.eu
Osv Id
UBUNTU-CVE-2026-40355
Osv Schema Version
1.7.0
Aliases
[]
Ecosystems
["Ubuntu:Pro:14.04:LTS","Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:20.04:LTS","Ubuntu:22.04:LTS","Ubuntu:24.04:LTS","Ubuntu:25.10","Ubuntu:26.04:LTS"]
Database Specific Severity
null
Cvss Version
3.1

Threat ID: 6a61511b9c2644c7f8da5d17

Added to database: 07/22/2026, 23:24:11 UTC

Last enriched: 07/22/2026, 23:52:09 UTC

Last updated: 07/31/2026, 19:22:58 UTC

Views: 5

Community Reviews

0 reviews

Crowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.

Sort by
Loading community insights…

Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.

Actions

PRO

Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.

Please log in to the Console to use AI analysis features.

Need more coverage?

Upgrade to Pro Console for AI refresh and higher limits.

For incident response and remediation, OffSeq services can help resolve threats faster.

Latest Threats

Breach by OffSeqOFFSEQFRIENDS — 25% OFF

Check if your credentials are on the dark web

Instant breach scanning across billions of leaked records. Free tier available.

Scan now
OffSeq TrainingCredly Certified

Lead Pen Test Professional

Technical5-day eLearningPECB Accredited
View courses