CVE-2023-39975

kdc/do_tgs_req.c in MIT Kerberos 5 (aka krb5) 1.21 before 1.21.2 has a double free that is reachable if an authenticated user can trigger an authorization-data handling failure. Incorrect data is copied from one ticket to another.

Published: 2023-08-16 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2023-39975 is rated Moderate Risk (57.8/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.23%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2023-39975

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 2026-06-15 1.31% 1.23% -0.08%
2 2026-06-12 1.23% 1.31% +0.08%
3 2026-02-24 — 1.23% —

Full EPSS history (16 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2023-39975

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 [email protected]
8.8 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.8 5.9 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2023-39975

OS Trackers for CVE-2023-39975

vendor priority summary link
debian unimportant CVE-2023-39975 unimportant 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-2023-39975
gentoo normal CVE-2023-39975: 1 GLSA(s) (202405-11), 1 atom(s) (app-crypt/mit-krb5); latest impact normal. https://bugs.gentoo.org/buglist.cgi?quicksearch=CVE-2023-39975
redhat high — https://access.redhat.com/security/cve/CVE-2023-39975
suse high CVE-2023-39975 severity important: SUSE including 36 source package names (krb5, krb5-1.21.2-1.1, …), 340 product×package rows across 54 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 7, … (54 product lines)): Known Not Affected 314, Fixed 26. https://www.suse.com/security/cve/CVE-2023-39975/
ubuntu medium CVE-2023-39975 medium priority: Ubuntu including 1 source packages (krb5), 7 status rows across 7 suites (bionic, focal, jammy, lunar, trusty, upstream, xenial): not-affected 7. https://ubuntu.com/security/CVE-2023-39975

Affected software / configurations for CVE-2023-39975

Vendor Product Version Raw CPE
mit kerberos_5 >= 1.21, < 1.21.2 cpe:2.3:a:mit:kerberos_5:*:*:*:*:*:*:*:*

References for CVE-2023-39975

cvelogic Threat Intelligence