Description
The spnego_gss_accept_sec_context function in lib/gssapi/spnego/spnego_mech.c in MIT Kerberos 5 (aka krb5) 1.5 through 1.6.3, when SPNEGO is used, allows remote attackers to cause a denial of service (NULL pointer dereference and daemon crash) via invalid ContextFlags data in the reqFlags field in a negTokenInit token.
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | krb5 | 1.6.dfsg.4~beta1-13 | — |
| Debian 13 | krb5 | 1.6.dfsg.4~beta1-13 | — |
| Debian 12 | krb5 | 1.6.dfsg.4~beta1-13 | — |
| Debian 5.0 | krb5 | 1.6.dfsg.4~beta1-5lenny1 | DSA-1766-1 |
| Debian 4.0 | krb5 | 1.4.4-7etch7 | DSA-1766-1 |
Red Hat
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| RHEL 5 | krb5 +4 | 1.6.1-31.el5_3.3 | RHSA-2009:0408 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | krb5 | 1.15-1.1 | openSUSE-SU-2024:10004-1 |
Advisories 3
- RHSA-2009:0408 Red Hat Security Advisory: krb5 security update Red Hat Security Advisories (RHSA) · Jun 28, 2026
- DSA-1766-1 krb5 - several vulnerabilities Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2024:10004-1 krb5-1.15-1.1 on GA media SUSE / openSUSE Security Updates · Feb 4, 2026
References
- http://support.novell.com/docs/Readmes/InfoDocument/patchbuilder/readme_5047181.html
- 20090407 MITKRB5-SA-2009-001: multiple vulnerabilities in SPNEGO, ASN.1 decoder [CVE-2009-0844 CVE-2009-0845 CVE-2009-0847] mailing-list
- VU#662091 third-party-advisory
- 34257 vdb-entry
- ADV-2009-0847 vdb-entry
- 34347 third-party-advisory
- http://support.apple.com/kb/HT3549
- http://support.avaya.com/elmodocs2/security/ASA-2009-142.htm
- http://src.mit.edu/fisheye/browse/krb5/trunk/src/lib/gssapi/spnego/spnego_mech.c?r1=21875&r2=22084
- RHSA-2009:0408 vendor-advisory
- 34637 third-party-advisory
- 34640 third-party-advisory
- 35074 third-party-advisory
- MDVSA-2009:082 vendor-advisory
- 256728 vendor-advisory
- GLSA-200904-09 vendor-advisory
- http://support.novell.com/docs/Readmes/InfoDocument/patchbuilder/readme_5047180.html
- ADV-2009-0976 vdb-entry
- APPLE-SA-2009-05-12 vendor-advisory
- USN-755-1 vendor-advisory
- 34630 third-party-advisory
- http://www-01.ibm.com/support/docview.wss?uid=swg21396120
- ADV-2009-1057 vdb-entry
- http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2009-001.txt
- 34617 third-party-advisory
- 34628 third-party-advisory
- 34734 third-party-advisory
- kerberos-spnego-dos(49448) vdb-entry
- oval:org.mitre.oval:def:6449 vdb-entry signature
- ADV-2009-2248 vdb-entry
- TA09-133A third-party-advisory
- http://wiki.rpath.com/wiki/Advisories:rPSA-2009-0058
- ADV-2009-1297 vdb-entry
- 34622 third-party-advisory
- http://krbdev.mit.edu/rt/Ticket/Display.html?user=guest&pass=guest&id=6402
- FEDORA-2009-2852 vendor-advisory
- 1021867 vdb-entry
- FEDORA-2009-2834 vendor-advisory
- http://wiki.rpath.com/Advisories:rPSA-2009-0058
- oval:org.mitre.oval:def:10044 vdb-entry signature
- http://src.mit.edu/fisheye/changelog/krb5/?cs=22084
- 20090407 rPSA-2009-0058-1 krb5 krb5-server krb5-services krb5-test krb5-workstation mailing-list
- 34594 third-party-advisory
- ADV-2009-1106 vdb-entry