krb5: S4U2Self KDC crash when anon is restricted
Published Aug 1, 2016
6.5
MEDIUMCVSS 3.0
EPSS 4.62%
Description
The validate_as_request function in kdc_util.c in the Key Distribution Center (KDC) in MIT Kerberos 5 (aka krb5) before 1.13.6 and 1.4.x before 1.14.3, when restrict_anonymous_to_tgt is enabled, uses an incorrect client data structure, which allows remote authenticated users to cause a denial of service (NULL pointer dereference and daemon crash) via an S4U2Self request.
Affected products
No data.
- 1.13
- 1.13.1
- 1.13.2
- 1.13.3
- 1.13.4
- 1.13.5
- 1.13.6
- 1.14
- 1.14.1
- 1.14.2
No data.
Red Hat Enterprise Linux 7
krb5-0:1.14.1-26.el7
Fixed · RHSA-2016:2591
Red Hat Enterprise Linux 5
krb5
Not affected
Red Hat Enterprise Linux 6
krb5
Will not fix
Red Hat JBoss Enterprise Application Platform 6
krb5
Not affected
Red Hat JBoss Enterprise Application Platform 7
krb5
Not affected
Red Hat JBoss Enterprise Web Server 2
krb5
Not affected
Red Hat JBoss Enterprise Web Server 3
krb5
Not affected
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 7 | krb5-0:1.14.1-26.el7 | Fixed | RHSA-2016:2591 |
| Red Hat Enterprise Linux 5 | krb5 | Not affected | n/a |
| Red Hat Enterprise Linux 6 | krb5 | Will not fix | n/a |
| Red Hat JBoss Enterprise Application Platform 6 | krb5 | Not affected | n/a |
| Red Hat JBoss Enterprise Application Platform 7 | krb5 | Not affected | n/a |
| Red Hat JBoss Enterprise Web Server 2 | krb5 | Not affected | n/a |
| Red Hat JBoss Enterprise Web Server 3 | krb5 | Not affected | n/a |
No package ranges for this CVE.
Remediation
No remediation recorded yet.
Metrics
No CVSS v4.0 score for this CVE.
No CVSS v3.1 score for this CVE.
CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
1 other source (Red Hat) ▾
CVSS:3.0/AV:N/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
AV:N/AC:L/Au:S/C:N/I:N/A:P
This CVE is not in the KEV list.
No CISA SSVC assessment for this CVE yet.
Estimated probability of exploitation in the wild in the next 30 days (FIRST EPSS). As of Oct 1, 2026.
Score over time
2022–2026- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Percentile over time
- EPSS v2
- EPSS v3
- EPSS v4
- EPSS v5
Table of values (17 key points)
Flat stretches are collapsed; showing up to 120 newest points.
| Date | Score | Percentile | Model |
|---|---|---|---|
| Oct 1, 2026 | 4.62% (0.04620) | 91.41th | v5 (v2026.06.15) |
| Jun 15, 2026 | 4.62% (0.04620) | 90.48th | v5 (v2026.06.15) |
| May 27, 2026 | 4.32% (0.04320) | 89.04th | v4 (v2025.03.14) |
| Nov 11, 2025 | 3.26% (0.03262) | 86.65th | v4 (v2025.03.14) |
| Nov 9, 2025 | 5.55% (0.05551) | 89.83th | v4 (v2025.03.14) |
| Mar 17, 2025 | 1.15% (0.01154) | 77.06th | v4 (v2025.03.14) |
| Dec 17, 2024 | 2.86% (0.02857) | 90.45th | v3 (v2023.03.01) |
| Nov 1, 2023 | 4.89% (0.04888) | 91.88th | v3 (v2023.03.01) |
| Aug 13, 2023 | 3.90% (0.03901) | 90.80th | v3 (v2023.03.01) |
| Jul 4, 2023 | 3.84% (0.03839) | 90.61th | v3 (v2023.03.01) |
| May 22, 2023 | 2.74% (0.02745) | 89.01th | v3 (v2023.03.01) |
| Apr 13, 2023 | 2.00% (0.01997) | 87.11th | v3 (v2023.03.01) |
| Mar 7, 2023 | 2.12% (0.02119) | 87.41th | v3 (v2023.03.01) |
| Mar 6, 2023 | 1.81% (0.01815) | 77.08th | v2 (v2022.01.01) |
| Feb 23, 2023 | 1.81% (0.01815) | 77.03th | v2 (v2022.01.01) |
| Apr 1, 2022 | 1.81% (0.01815) | 75.00th | v2 (v2022.01.01) |
| Feb 4, 2022 | 1.81% (0.01815) | 54.30th | v2 (v2022.01.01) |
References (14)
- http://krbdev.mit.edu/rt/Ticket/Display.html?id=8458 x_refsource_CONFIRMIssue Tracking
- http://lists.opensuse.org/opensuse-updates/2016-09/msg00035.html vendor-advisoryx_refsource_SUSE
- http://rhn.redhat.com/errata/RHSA-2016-2591.html vendor-advisoryx_refsource_REDHAT
- http://web.mit.edu/kerberos/krb5-1.13/ x_refsource_CONFIRM
- http://web.mit.edu/kerberos/krb5-1.14/ x_refsource_CONFIRM
- http://www.securityfocus.com/bid/92132 vdb-entryx_refsource_BID
- http://www.securitytracker.com/id/1036442 vdb-entryx_refsource_SECTRACK
- https://access.redhat.com/security/cve/CVE-2016-3120 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=1361050 Issue Tracking
- https://github.com/krb5/krb5/commit/93b4a6306a0026cf1cc31ac4bd8a49ba5d034ba7 x_refsource_CONFIRM
- https://lists.debian.org/debian-lts-announce/2018/01/msg00040.html mailing-listx_refsource_MLIST
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/AWL3KYFRJIX37EAM4DKCQQIQP2WBKL35/ vendor-advisoryx_refsource_FEDORA
- https://nvd.nist.gov/vuln/detail/CVE-2016-3120
- https://www.cve.org/CVERecord?id=CVE-2016-3120
Change history (0)
No recorded changes yet.