NVD / CVE Program· CNA GitHub_M

CVE-2026-56727: Zammad: PGP signature spoofing via unvalidated verification return

HighCVSS 7.1 · v4.0—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 28/100)

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: 0.24% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. No account or password is required. No special conditions are required; it is repeatable.
According to CISA the attack is automatable: targets can be found by mass scanning.
Fixed version: zammad zammad 7.0.2.

Low priority for now. Upgrade to zammad zammad 7.0.2 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

Zammad is a web based open source helpdesk/customer support system. Prior to 7.0.2, summary In Zammad's inbound PGP email processing, the return value of the gpg verification call was silently discarded. Regardless of whether gpg reported a valid, invalid, or missing signature, the handler unconditionally wrote sign: { success: true, comment: "Good signature" } to the article's security preferences. Impact Any sender could tamper with the body of a multipart/signed PGP email, or craft a message with an entirely fabricated or mismatched signature, and Zammad would display it to the recipient as cryptographically verified with a "Good signature" label. Users and agents relying on Zammad's signature indicator to confirm message authenticity and integrity would be misled into trusting modified or forged content. The vulnerability affects all inbound PGP-signed emails processed while the PGP integration is enabled. This issue is fixed in version 7.0.2.

EUVD-2026-87214

Published: Sep 25, 2026
Updated: Sep 28, 2026
EPSS: 0.2% · 16th percentile
CWE: CWE-287

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 28 / 40 · 7.1 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.2%

CISA SSVC decision

Exploitation: none
Automatable: yes
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · GitHub_M: 7.1; NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N

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.

Is your version affected? Check it

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?

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—

Versions reported by the vendor

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

zammad zammad
- < 7.0.2affected

Same product

zammad: all records

Other highest-scoring records for the same primary product.

CVE-2026-102489Undisclosed RCE in Zammad v6.3 and higherKEV
82Now
CVE-2026-102490Local privilege escalation in Zammad v1.5.0 to v7.2.2 installed via DEB or RPM packageKEV
70This week
CVE-2021-42090An issue was discovered in Zammad before 4.1.1.
40Plan

Published before and after this one in the same product

← EarlierCVE-2026-56729Sep 25, 2026 · Zammad: Titles of knowledge base answers will be shown across all categories via the global search
8Monitor
← EarlierCVE-2026-56726Sep 25, 2026 · Zammad: Missing authorization check in GitHub + GitLab integration allows cross-ticket data leak
20Monitor
Later →CVE-2026-56728Sep 25, 2026 · Zammad: Cross-User Taskbar Item Access Control Vulnerability
21Monitor

Remediation

Which version to upgrade to

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

Product / package	Fixed version	Source
zammad zammad	7.0.2 · description	Vendor (CNA)

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.

zammad/zammadcommit 4a9dd5f

Variant candidates

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

CVE-2026-844580 days apartZammad: Account takeover via unverified email matching during SSO auto-link
36Monitor

Chain candidates

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

CVE-2026-844620 days apartZammad: AI Agent template sanitizer bypass leads to remote code execution
34Monitor
CVE-2026-34724170 days apartZammad has a server-side template injection leading to RCE via AI Agent
34Monitor
CVE-2026-34719170 days apartZammad has a Server-side request forgery (SSRF) via webhooks
33Monitor
CVE-2026-567340 days apartZammad: Avatar Image URL Server-Side Request Forwarding
21Monitor

Not on record for this CVE: researcher credit · public bounty program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
No account or password is required.
No special conditions are required; it is repeatable.

If successful

Confidentiality
Integrity
Availability

Attack vector: Network
Attack complexity: Low
Privileges required: None
User interaction: P
Scope: X

Weakness class (CWE)

CWE-287 · Improper Authentication

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

Authentication is added route by route instead of being enforced in one place. When a route added later bypasses the shared middleware, the session check never runs for it.

The bug in code

The whole CWE-287 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

1app.use("/admin", requireSession, adminRouter);
2

3// Route added later skips the middleware
4app.post("/admin-api/config", updateConfig);

Fixed

1const admin = express.Router();
2admin.use(requireSession, requireRole("admin"));
3

4admin.post("/config", updateConfig);
5app.use("/admin", admin);

Attack context

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

Attack patterns (CAPEC)

ATT&CK techniques

Change log (1)

Fix✗ → ✓Sep 29, 2026, 11:57 AM UTC

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

References

github.com/zammad/zammad/commit/4a9dd5f8a85948c5a2f96f6479d785153aac05d7

Show all references (2 more)

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

All records