CVE-2026-84465

HIGHPre-NVD 7.17.1—
EchelonGraph scoreMEDIUM confidence

This high-severity CVE scores 7.1 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.1% (1st percentile of EPSS-scored CVEs). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
7.1EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 7.1Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when Zammad checks the digital signature on an incoming S/MIME-signed email, it does not verify that the signing certificate is genuinely trusted, it only checks whether a certificate with a matching name is already stored in the system. An attacker can create their own certificate using the name of a real, previously trusted sender and use it to send a forged email. Zammad will display that email with the same "validly signed" indicator as a genuine message from the real sender, even though the attacker never had access to that sender's actual certificate or private key. This issue is fixed in version 7.1.2.

CVSS v3
7.1
EG Score
7.1HIGHmedium confidence
EG Risk
47
EG Risk 47/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity71% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.1%
EPSS %ILE
1st
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 25, 2026

Last Modified

September 29, 2026

Advisory Details (2)

Auto-updated Sep 25, 2026
Patch available. Sources: github, github_commit.
github_commit

commit 9a07d0b8214a (zammad/zammad)

Fix landed in zammad/zammad commit 9a07d0b8214a — awaiting tagged release

https://github.com/zammad/zammad/commit/9a07d0b8214ac4e8e10c23fce71d613bd0625524
github Patch Available

S/MIME signature verification allows forged sender impersonation · Advisory · zammad/zammad · GitHub

https://github.com/zammad/zammad/security/advisories/GHSA-m9ff-hjr3-93h4

Weakness Classification(3)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 16× in last 7d / 21× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-03 14:52 UTCEG score recompute
  2. 2026-10-03 14:26 UTCEPSS rescore
  3. 2026-10-03 01:56 UTCEG score recompute
  4. 2026-10-02 17:57 UTCEPSS rescore
  5. 2026-10-02 00:03 UTCEG score recompute
  6. 2026-10-01 19:50 UTCEPSS rescore
  7. 2026-09-30 21:18 UTCEG score recompute
  8. 2026-09-30 15:04 UTCEPSS rescore
  9. 2026-09-29 19:22 UTCEG score recompute
  10. 2026-09-29 18:33 UTCEG score recompute
  11. 2026-09-29 16:46 UTCEG score recompute
  12. 2026-09-29 03:48 UTCEG score recompute
  13. 2026-09-28 14:51 UTCEG score recompute
  14. 2026-09-28 13:52 UTCEPSS rescore
  15. 2026-09-27 23:27 UTCEG score recompute
  16. 2026-09-27 13:48 UTCEPSS rescore
  17. 2026-09-26 21:30 UTCEG score recompute
  18. 2026-09-26 15:59 UTCEPSS rescore
  19. 2026-09-25 19:34 UTCEG score recompute
  20. 2026-09-25 18:32 UTCEG score recompute
  21. 2026-09-25 18:30 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-84465?
CVE-2026-84465 is a high vulnerability published on September 25, 2026. Zammad is a web based open source helpdesk/customer support system. Prior to 7.1.2, when Zammad checks the digital signature on an incoming S/MIME-signed email, it does not verify that the signing certificate is genuinely trusted, it only checks whether a certificate with a matching name is already…
When was CVE-2026-84465 disclosed?
CVE-2026-84465 was first published on September 25, 2026, with the most recent update on September 29, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-84465 actively exploited?
CVE-2026-84465 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (1st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-84465?
CVE-2026-84465 has a CVSS base score of 7.1 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-84465?
A fix for CVE-2026-84465 is available: update to the fixed version the vendor names in its advisory.

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