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CVE-2025-3576· NVD / CVE Program· CNA redhat

Krb5: kerberos rc4-hmac-md5 checksum vulnerability enabling message spoofing via md5 collisions

Noroxi assessment

Priority: Monitor (action score 23/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.35% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. Special conditions such as timing or configuration are required.
  • Fixed version: web.mit.edu/kerberos/ krb5 1.22; azl3 krb5 1.21.3-2 on Azure Linux 3.0 CBL-Mariner Releases; cbl2 krb5 1.19.4-3 on CBL Mariner 2.0 1.19.4-4.

Low priority for now. Upgrade to web.mit.edu/kerberos/ krb5 1.22; azl3 krb5 1.21.3-2 on Azure Linux 3.0 CBL-Mariner Releases; cbl2 krb5 1.19.4-3 on CBL Mariner 2.0 1.19.4-4 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

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.

MediumCVSS 5.9 · v3.1—No exploit Fix available
Published
Apr 15, 2025
Updated
Sep 1, 2026
EPSS
0.3% · 27th percentile

Report tools

JSON

Action score

23

Monitor

Low priority for now.

CVSS
23 / 40 · 5.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · redhat
5.9
NVD has not scored this yet; the score shown is the CNA’s.

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2025-3576

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (redhat). Independent of NVD's CPE analysis and usually ahead of it.

  • Red Hat Red Hat Discovery 2

    • 2.0.0-1752592913 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 10

    • 0:1.21.3-8.el10_0 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 6

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 7

    • all versionsunknown

  • Red Hat Red Hat Enterprise Linux 8

    • 0:1.18.2-32.el8_10 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.2 Advanced Update Support

    • 0:1.17-19.el8_2.3 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support

    • 0:1.18.2-9.el8_4.3 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

    • 0:1.18.2-9.el8_4.3 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support

    • 0:1.18.2-16.el8_6.4 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.6 Telecommunications Update Service

    • 0:1.18.2-16.el8_6.4 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions

    • 0:1.18.2-16.el8_6.4 and laternot affected · rpm

  • Red Hat Red Hat Enterprise Linux 8.8 Telecommunications Update Service

    • 0:1.18.2-26.el8_8.5 and laternot affected · rpm

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:10krb5-develbefore 1.21.3-8.el10_01.21.3-8.el10_0
AlmaLinux:10krb5-libsbefore 1.21.3-8.el10_01.21.3-8.el10_0
AlmaLinux:10krb5-pkinitbefore 1.21.3-8.el10_01.21.3-8.el10_0
AlmaLinux:10krb5-serverbefore 1.21.3-8.el10_01.21.3-8.el10_0
AlmaLinux:10krb5-server-ldapbefore 1.21.3-8.el10_01.21.3-8.el10_0
AlmaLinux:10krb5-workstationbefore 1.21.3-8.el10_01.21.3-8.el10_0
AlmaLinux:10libkadm5before 1.21.3-8.el10_01.21.3-8.el10_0
AlmaLinux:8krb5-develbefore 1.18.2-32.el8_101.18.2-32.el8_10
AlmaLinux:8krb5-libsbefore 1.18.2-32.el8_101.18.2-32.el8_10
AlmaLinux:8krb5-pkinitbefore 1.18.2-32.el8_101.18.2-32.el8_10
AlmaLinux:8krb5-serverbefore 1.18.2-32.el8_101.18.2-32.el8_10
AlmaLinux:8krb5-server-ldapbefore 1.18.2-32.el8_101.18.2-32.el8_10
AlmaLinux:8krb5-workstationbefore 1.18.2-32.el8_101.18.2-32.el8_10
AlmaLinux:8libkadm5before 1.18.2-32.el8_101.18.2-32.el8_10
AlmaLinux:9krb5-develbefore 1.21.1-8.el9_61.21.1-8.el9_6
AlmaLinux:9krb5-libsbefore 1.21.1-8.el9_61.21.1-8.el9_6
AlmaLinux:9krb5-pkinitbefore 1.21.1-8.el9_61.21.1-8.el9_6
AlmaLinux:9krb5-serverbefore 1.21.1-8.el9_61.21.1-8.el9_6
AlmaLinux:9krb5-server-ldapbefore 1.21.1-8.el9_61.21.1-8.el9_6
AlmaLinux:9krb5-workstationbefore 1.21.1-8.el9_61.21.1-8.el9_6
AlmaLinux:9libkadm5before 1.21.1-8.el9_61.21.1-8.el9_6
Debian:11krb5before 1.18.3-6+deb11u71.18.3-6+deb11u7
Debian:12krb5before 1.20.1-2+deb12u41.20.1-2+deb12u4
Debian:13krb5before 1.21.2-11.21.2-1

+96

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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
web.mit.edu/kerberos/ krb51.22Vendor (CNA)
azl3 krb5 1.21.3-2 on Azure Linux 3.0CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 krb5 1.19.4-3 on CBL Mariner 2.01.19.4-4 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 krb5 1.19.4-4 on CBL Mariner 2.01.19.4-4 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 krb5 1.19.4-4 on CBL-Mariner 2.01.19.4-4 · CBL-Mariner ReleasesMicrosoft (MSRC)
almalinux:krb5-devel1.18.2-32.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:krb5-libs1.18.2-32.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:krb5-pkinit1.18.2-32.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:krb5-server1.18.2-32.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:krb5-server-ldap1.18.2-32.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:krb5-workstation1.18.2-32.el8_10 · AlmaLinux:8Package registry (OSV)
almalinux:libkadm51.18.2-32.el8_10 · AlmaLinux:8Package registry (OSV)
debian:krb51.20.1-2+deb12u4 · Debian:12Package registry (OSV)
opensuse:krb51.20.1-150600.11.14.1 · openSUSE:Leap 15.6Package registry (OSV)
red hat:krb50:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::baseosPackage registry (OSV)
red hat:krb5-debuginfo0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:krb5-debugsource0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:krb5-devel0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:krb5-libs0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::baseosPackage registry (OSV)
red hat:krb5-libs-debuginfo0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:krb5-pkinit0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::baseosPackage registry (OSV)
red hat:krb5-pkinit-debuginfo0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:krb5-server-debuginfo0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:krb5-server-ldap-debuginfo0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:krb5-workstation-debuginfo0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:libkadm5-debuginfo0:1.21.1-2.el9_4.2 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
rocky linux:krb50:1.18.2-32.el8_10 · Rocky Linux:8Package registry (OSV)
suse:krb51.19.2-150300.25.1 · SUSE:Linux Enterprise Micro 5.1Package registry (OSV)
suse:krb51.20.1-150600.11.14.1 · SUSE:Linux Enterprise Module for Basesystem 15 SP6Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
none
Integrity
high · data or configuration can be modified
Availability
none
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
High
Availability impact
None

Weakness class (CWE)

CWE-328 · Use of Weak Hash

CVSS vector

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (15 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records