Multiple integer underflows in the (1) AES and (2) RC4 decryption functionality in the crypto library in MIT Kerberos 5 (aka krb5) 1.3 through 1.6.3, and 1.7 before 1.7.1, allow remote attackers to cause a denial of service (daemon crash) or possibly execute arbitrary code by providing ciphertext with a length that is too short to be valid.
Conclusion & alert: CVE-2009-4212 is rated High Risk (68.7/100): CVSS Critical severity, with high exploitation likelihood (EPSS 16.48%, 95th percentile). Core evidence: EPSS ranks this CVE among the most likely to be exploited in the near term. Mandatory action: High exploitation likelihood—assess exposure and prioritize remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).
| # | Date | Old EPSS score | New EPSS score | Delta (New - Old) |
|---|---|---|---|---|
| 1 | 2025-11-09 | 20.91% | 16.48% | -4.43% |
| 2 | 2025-03-30 | 29.32% | 20.91% | -8.41% |
| 3 | 2025-03-29 | — | 29.32% | — |
Full EPSS history (8 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 10.0 | 2.0 | HIGH |
|
10.0 | 10.0 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
debian
|
not yet assigned | CVE-2009-4212 not yet assigned priority: Debian including 1 source packages (krb5), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. | https://security-tracker.debian.org/tracker/CVE-2009-4212 |
gentoo
|
high | CVE-2009-4212: 1 GLSA(s) (201201-13), 1 atom(s) (app-crypt/mit-krb5); latest impact high. | https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2009-4212 |
redhat
|
critical | — | https://access.redhat.com/security/cve/CVE-2009-4212 |
suse
|
critical | CVE-2009-4212 severity critical: SUSE including 115 source package names (krb5-1.12.1-19.1, krb5-1.12.1-6.3, …), 170 product×package rows across 34 product lines (SUSE Linux Enterprise Desktop 12, SUSE Linux Enterprise Desktop 12 SP1, … (34 product lines)): Fixed 170. | https://www.suse.com/security/cve/CVE-2009-4212/ |
ubuntu
|
medium | CVE-2009-4212 medium priority: Ubuntu including 1 source packages (krb5), 6 status rows across 6 suites (dapper, hardy, intrepid, jaunty, karmic, upstream): released 6. | https://ubuntu.com/security/CVE-2009-4212 |
: Per: http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2009-004.txt "Only releases krb5-1.3 and later are vulnerable, as earlier releases did not contain the functionality implemented by the vulnerable code. This is an implementation vulnerability in MIT krb5, and is not a vulnerability in the Kerberos protocol."
: Per: http://web.mit.edu/kerberos/advisories/MITKRB5-SA-2009-004.txt FIXES ===== * The upcoming krb5-1.7.1 and krb5-1.6.4 releases will contain a fix for this vulnerability. * For the krb5-1.7 release, apply the patch available at: http://web.mit.edu/kerberos/advisories/2009-004-patch_1.7.txt A PGP-signed patch is available at http://web.mit.edu/kerberos/advisories/2009-004-patch_1.7.txt.asc * For the krb5-1.6 releases, apply the patch available at: http://web.mit.edu/kerberos/advisories/2009-004-patch_1.6.3.txt A PGP-signed patch is available at http://web.mit.edu/kerberos/advisories/2009-004-patch_1.6.3.txt.asc * The krb5-1.6.3 patch might apply successfully to older releases.
| Vendor | Product | Version | Raw CPE |
|---|---|---|---|
| mit | kerberos | 5-1.6.3 | cpe:2.3:a:mit:kerberos:5-1.6.3:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.3 | cpe:2.3:a:mit:kerberos_5:1.3:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.3.1 | cpe:2.3:a:mit:kerberos_5:1.3.1:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.3.2 | cpe:2.3:a:mit:kerberos_5:1.3.2:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.3.3 | cpe:2.3:a:mit:kerberos_5:1.3.3:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.3.4 | cpe:2.3:a:mit:kerberos_5:1.3.4:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.3.5 | cpe:2.3:a:mit:kerberos_5:1.3.5:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.3.6 | cpe:2.3:a:mit:kerberos_5:1.3.6:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.4 | cpe:2.3:a:mit:kerberos_5:1.4:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.4.1 | cpe:2.3:a:mit:kerberos_5:1.4.1:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.4.2 | cpe:2.3:a:mit:kerberos_5:1.4.2:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.4.3 | cpe:2.3:a:mit:kerberos_5:1.4.3:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.4.4 | cpe:2.3:a:mit:kerberos_5:1.4.4:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.5 | cpe:2.3:a:mit:kerberos_5:1.5:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.5.1 | cpe:2.3:a:mit:kerberos_5:1.5.1:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.5.2 | cpe:2.3:a:mit:kerberos_5:1.5.2:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.5.3 | cpe:2.3:a:mit:kerberos_5:1.5.3:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.6 | cpe:2.3:a:mit:kerberos_5:1.6:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.6.1 | cpe:2.3:a:mit:kerberos_5:1.6.1:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.6.2 | cpe:2.3:a:mit:kerberos_5:1.6.2:*:*:*:*:*:*:* |
| mit | kerberos_5 | 1.7 | cpe:2.3:a:mit:kerberos_5:1.7:*:*:*:*:*:*:* |