NVD / CVE Program· CNA Mattermost

CVE-2024-36255: Post actions can run playbook checklist task commands

Noroxi assessment

Priority: Monitor (action score 22/100)

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: 0.18% (FIRST EPSS).
Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. A user must open a link or visit a page. No special conditions are required; it is repeatable.
According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

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

Mattermost versions 9.5.x <= 9.5.3, 9.6.x <= 9.6.1 and 8.1.x <= 8.1.12 fail to perform proper input validation on post actions which allows an attacker to run a playbook checklist task command as another user via creating and sharing a deceptive post action that unexpectedly runs a slash command in some arbitrary channel.

MediumCVSS 5.7 · v3.1—No exploit No fix recorded

CSRF

Published: May 26, 2024
Updated: Jun 17, 2026
EPSS: 0.1% · 8th percentile
CWE: CWE-352

Report tools

JSON

Action score

Monitor

Low priority for now.

CVSS: 22 / 40 · 5.7 / 10
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

CISA SSVC decision

Exploitation: none
Automatable: no
Technical impact: partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD: —
CNA · Mattermost: 5.7; 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
No fixed version yet

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

Running WordPress? Scan your site free with WP Lens

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.

We use this product, ask for help

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.

Vendor	Product	CPE
mattermost	mattermost server	cpe:2.3:a:mattermost:mattermost_server

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

mattermost mattermost server8.1.0 and later · before 8.1.13
mattermost mattermost server9.5.0 and later · before 9.5.4
mattermost mattermost server9.6.0 and later · before 9.6.2

Versions reported by the vendor

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

Mattermost Mattermost
- 9.7.0, 9.5.4, 9.6.2, 8.1.13not affected
- 9.5.0 and later · up to and including 9.5.3affected · semver
- 9.6.0 and later · up to and including 9.6.1affected · semver
- 8.1.0 and later · up to and including 8.1.12affected · semver

Same product

mattermost: all records

Other highest-scoring records for the same primary product.

CVE-2026-4858Path traversal in integration action URL leading to arbitrary API execution via system admin’s auth token.
39Monitor
CVE-2025-12421Account Takeover via Code Exchange Endpoint
39Monitor
CVE-2025-12419Account takeover on OAuth/OpenID-enabled servers
39Monitor

Published before and after this one in the same product

← EarlierCVE-2024-34152May 26, 2024 · Playbook Run Metadata leak to Guest
17Monitor
← EarlierCVE-2024-36241May 26, 2024 · /playbook add slash command allows viewing arbitrary post contents
17Monitor
Later →CVE-2024-5270May 26, 2024 · SAML to email switch possible when email signin is disabled
17Monitor

Remediation

Which version to upgrade to

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

No fix version is recorded for this entry. Check the references for vendor advisories.

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.

No history yet (it accumulates with the daily EPSS job).

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.

Juho NurminenMattermostfinder

Variant candidates

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

CVE-2023-45316166 days apartReflected client side path traversal leading to CSRF in Playbooks
35Monitor
CVE-2024-46872156 days apartClient-Side Path Traversal Leading to CSRF in Playbooks
18Monitor
CVE-2024-23319107 days apartCSRF issue allows disconnecting a user's Jira connection through a simple post message (Jira Plugin)
14Monitor

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

Mattermost Public Bug Bounty Engagement Bugcrowd · paid · up to $2,000

The product’s vendor appears in a public program. Matched by name; verify the scope text in the program.

Technical details

Attack conditions

Anyone who can reach it over the internet can trigger it.
A low-privileged account is enough.
A user must open a link or visit a page.
No special conditions are required; it is repeatable.

If successful

Confidentiality: none
Integrity: high · data or configuration can be modified
Availability: none

Attack vector: Network
Attack complexity: Low
Privileges required: Low
User interaction: Required
Scope: Unchanged
Confidentiality impact: None
Integrity impact: High
Availability impact: None

Weakness class (CWE)

CWE-352 · Cross-Site Request Forgery (CSRF)

CVSS vector

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

nvd-secondary

Root cause

State-changing requests rely on the session cookie the browser sends automatically; nothing verifies that the request came from the user’s own page.

The bug in code

The whole CWE-352 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(session({ cookie: { httpOnly: true } }));
2app.post("/account/address", updateAddress);

Fixed

1app.use(session({ cookie: { httpOnly: true, sameSite: "lax" } }));
2app.post("/account/address", csrfProtection, updateAddress);

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

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

mattermost.com/security-updates

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

All records