CVE-2025-3576 | Krb5: kerberos rc4-hmac-md5 checksum vulnerability enabling message spoofing via md5 collisions

A vulnerability in the MIT Kerberos implementation allows GSSAPI-protected messages using RC4-HMAC-MD5 to be spoofed due to weaknesses in the MD5 checksum design. If RC4 is preferred over stronger encryption types, an attacker could exploit MD5 collisions to forge message integrity codes. This may lead to unauthorized message tampering.

Published: 2025-04-15 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]

Conclusion & alert: CVE-2025-3576 is rated Moderate Risk (40.9/100): CVSS Medium severity, with low exploitation likelihood (EPSS 0.26%). Mandatory action: 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-2025-3576

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 2026-05-24 0.23% 0.26% +0.03%
2 2026-02-20 0.26% 0.23% -0.03%
3 2026-02-09 0.26%

Full EPSS history (9 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2025-3576

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
5.9 3.1 MEDIUM
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N 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:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
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:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
2.2 3.6 [email protected]

Weakness enumeration for CVE-2025-3576

GitHub Security Advisory for CVE-2025-3576

GHSA-rfh5-gx7w-h7v7 · Severity: medium — A vulnerability in the MIT Kerberos implementation allows GSSAPI-protected messages using RC4...

OS Trackers for CVE-2025-3576

vendor priority summary link
debian not yet assigned CVE-2025-3576 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-2025-3576
redhat medium https://access.redhat.com/security/cve/CVE-2025-3576
suse medium CVE-2025-3576 severity moderate: SUSE including 357 source package names (0.0.17-1.1:krb5-1.20.1-150600.11.14.1, 0.1.6-2.11:krb5-1.20.1-150600.11.14.1, …), 937 product×package rows across 362 product lines (Container bci/kiwi, Container bci/spack, … (362 product lines)): Fixed 687, Known Affected 226, Known Not Affected 24. https://www.suse.com/security/cve/CVE-2025-3576/
ubuntu medium CVE-2025-3576 medium priority: Ubuntu including 1 source packages (krb5), 10 status rows across 10 suites (bionic, focal, jammy, noble, oracular, plucky, questing, trusty, upstream, xenial): released 7, not-affected 3. https://ubuntu.com/security/CVE-2025-3576

Affected software / configurations for CVE-2025-3576

Vendor Product Version Raw CPE
No affected products in dataset.

References for CVE-2025-3576

URL Tags
https://access.redhat.com/errata/RHSA-2025:11487
https://access.redhat.com/errata/RHSA-2025:13664
https://access.redhat.com/errata/RHSA-2025:13777
https://access.redhat.com/errata/RHSA-2025:15000
https://access.redhat.com/errata/RHSA-2025:15001
https://access.redhat.com/errata/RHSA-2025:15002
https://access.redhat.com/errata/RHSA-2025:15003
https://access.redhat.com/errata/RHSA-2025:15004
https://access.redhat.com/errata/RHSA-2025:8411
https://access.redhat.com/errata/RHSA-2025:9418
https://access.redhat.com/errata/RHSA-2025:9430
https://access.redhat.com/security/cve/CVE-2025-3576
https://bugzilla.redhat.com/show_bug.cgi?id=2359465
https://web.mit.edu/kerberos/krb5-1.22/krb5-1.22.html
https://lists.debian.org/debian-lts-announce/2025/05/msg00047.html
https://cert-portal.siemens.com/productcert/html/ssa-577017.html
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