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

Status: published. Published: 2025-04-15. Updated: 2026-11-05.

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.

## Remediation

- workaround: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability. (source: CNA: redhat)

## Affected products and versions

-  /  (krb5): ≥ 0; < 1.22 (affected, semver). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 10 (krb5): ≥ 0:1.21.3-8.el10_0; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8 (krb5): ≥ 0:1.18.2-32.el8_10; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.2 Advanced Update Support (krb5): ≥ 0:1.17-19.el8_2.3; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support (krb5): ≥ 0:1.18.2-9.el8_4.3; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On (krb5): ≥ 0:1.18.2-9.el8_4.3; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support (krb5): ≥ 0:1.18.2-16.el8_6.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Telecommunications Update Service (krb5): ≥ 0:1.18.2-16.el8_6.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.6 Update Services for SAP Solutions (krb5): ≥ 0:1.18.2-16.el8_6.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Telecommunications Update Service (krb5): ≥ 0:1.18.2-26.el8_8.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions (krb5): ≥ 0:1.18.2-26.el8_8.5; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9 (krb5): ≥ 0:1.21.1-8.el9_6; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.0 Update Services for SAP Solutions (krb5): ≥ 0:1.19.1-16.el9_0.4; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions (krb5): ≥ 0:1.20.1-9.el9_2.3; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 9.4 Extended Update Support (krb5): ≥ 0:1.21.1-2.el9_4.2; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Discovery 2 (discovery/discovery-server-rhel9): ≥ 2.0.0-1752592913; < * (unaffected, rpm). Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 6 (krb5): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat Enterprise Linux 7 (krb5): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-8): Version range not reported. Source: CNA: redhat
- Red Hat / Red Hat OpenShift Container Platform 4 (openshift/ose-rhel-coreos-9): Version range not reported. Source: CNA: redhat
- Siemens / RUGGEDCOM ROX MX5000: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX MX5000RE: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX RX1400: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX RX1500: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX RX1501: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX RX1510: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX RX1511: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX RX1512: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX RX1524: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX RX1536: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP
- Siemens / RUGGEDCOM ROX RX5000: ≥ 0; < V2.17.1 (affected, custom). Source: ADP: siemens-SADP

## Severity and prioritization

- CVSS 3.1: 5.9 (medium); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N; source: CNA: redhat

- CISA KEV: No listing in collected sources

- EPSS: 0.35% as of 2026-11-05; percentile 28.91%

- SSVC: exploitation none; automatable no; technical impact partial; source ADP: CISA-ADP

- Weaknesses: CWE-328

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://access.redhat.com/errata/RHSA-2025:11487 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:13664 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:13777 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:15000 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:15001 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:15002 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:15003 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:15004 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:8411 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:9418 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/errata/RHSA-2025:9430 (CNA: redhat; vendor-advisory, x_refsource_REDHAT)

- https://access.redhat.com/security/cve/CVE-2025-3576 (CNA: redhat; vdb-entry, x_refsource_REDHAT)

- https://bugzilla.redhat.com/show_bug.cgi?id=2359465 (CNA: redhat; issue-tracking, x_refsource_REDHAT)

- https://web.mit.edu/kerberos/krb5-1.22/krb5-1.22.html (CNA: redhat)

- https://lists.debian.org/debian-lts-announce/2025/05/msg00047.html (ADP: CVE)

- https://cert-portal.siemens.com/productcert/html/ssa-577017.html (ADP: siemens-SADP)

## Provenance

- CNA: redhat: https://www.cve.org/CVERecord?id=CVE-2025-3576; retrieved 2026-11-05; source updated 2026-11-05

- FIRST EPSS: https://api.first.org/data/v1/epss?cve=CVE-2025-3576; retrieved 2026-11-05; source updated Not reported

Revision: d57dbe1d5d7699575fc34cc6bfbc13d7e5ed4e3dfb4339be738ce4026e3d8c97

Canonical: https://y2.dev/cve/CVE-2025-3576

## Agent and API access

Public CVE pages, Markdown, and JSON are free to read without an account or API key.

- Public catalog: https://y2.dev/cve/index.json. Follow nextCursor with the same search, filters, sort, and limit (1–100). A null cursor marks the end.

- WebMCP: search_cve_disclosures, get_cve_disclosure, get_cve_page_markdown, get_y2_cve_access. Available in compatible browsers.

- Cyber API: https://api.y2.dev/api/v2/cyber/cves and https://api.y2.dev/api/v2/cyber/cves/{cveId}.

- Y2 Pro or Elite: create a workspace API key with the intel:cyber scope and send Authorization: Bearer <Y2_API_KEY>. Setup: https://y2.dev/docs/api/create-key.

- x402: Pay per request without an account or API key. Omit Authorization, read the HTTP 402 PAYMENT-REQUIRED challenge, validate its current requirements, and retry with PAYMENT-SIGNATURE through an authorized payment client. These browser tools never make payments. Guide: https://y2.dev/docs/api/x402.

- OpenAPI: https://y2.dev/api/openapi.yaml. Agent access metadata: https://y2.dev/cve/agent.json.

Collected public records only. Check source status for coverage and freshness.