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CVE-2025-9072· NVD / CVE Program· CNA Mattermost

One-Click Mattermost Account Takeover via Poisoned RelayState SAML Parameter

Mattermost versions 10.10.x <= 10.10.1, 10.5.x <= 10.5.9, 10.9.x <= 10.9.4 fail to validate the redirect_to parameter, allowing an attacker to craft a malicious link that, once a user authenticates with their SAML provider, could post the user’s cookies to an attacker-controlled URL.

MediumCVSS 5.4 · v3.1—No exploit Fix available
Published
Sep 15, 2025
Updated
Jun 17, 2026
EPSS
0.2% · 6th percentile
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Action score

21

Monitor

Low priority for now.

CVSS
21 / 40 · 5.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.4
CNA · Mattermost
7.6
2.2 point gap

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

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

Affected systems

VendorProduct
mattermostmattermost server

Affected versions

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

  • mattermost mattermost server10.5.0 and later · before 10.5.10
  • mattermost mattermost server10.9.0 and later · before 10.9.5
  • mattermost mattermost server10.10.0 and later · before 10.10.2

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

    • 10.11.0, 10.10.2, 10.5.10, 10.9.5not affected
    • 10.10.0 and later · up to and including 10.10.1affected · semver
    • 10.5.0 and later · up to and including 10.5.9affected · semver
    • 10.9.0 and later · up to and including 10.9.4affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Gogithub.com/mattermost/mattermost-serverfrom 10.10.0 · before 10.10.210.10.2
Gogithub.com/mattermost/mattermost-serverfrom 10.10.0+incompatible · before 10.10.2+incompatible10.10.2+incompatible
Gogithub.com/mattermost/mattermost-serverfrom 10.5.0 · before 10.5.1010.5.10
Gogithub.com/mattermost/mattermost-serverfrom 10.5.0+incompatible · before 10.5.10+incompatible10.5.10+incompatible
Gogithub.com/mattermost/mattermost-serverfrom 10.9.0 · before 10.9.510.9.5
Gogithub.com/mattermost/mattermost-serverfrom 10.9.0+incompatible · before 10.9.5+incompatible10.9.5+incompatible
Gogithub.com/mattermost/mattermost-server/v5all versions—
Gogithub.com/mattermost/mattermost-server/v6all versions—
Gogithub.com/mattermost/mattermost/server/v8before 8.0.0-20250731063404-9eebaadf8f728.0.0-20250731063404-9eebaadf8f72
openSUSE:Tumbleweedgovulncheck-vulndbbefore 0.0.20250917T170349-1.10.0.20250917T170349-1.1

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
  • CVE-2025-4981Path Traversal Leading to RCE by Any Authenticated Mattermost User
    39Monitor
  • CVE-2023-6458Client side path traversal due to lack of route parameters validation
    39Monitor
  • CVE-2017-18920An issue was discovered in Mattermost Server before 3.6.2.
    39Monitor

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
Go:github.com/mattermost/mattermost-server10.10.2Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.10.2+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost-server10.5.10Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.5.10+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost-server10.9.5Package registry (OSV)
Go:github.com/mattermost/mattermost-server10.9.5+incompatiblePackage registry (OSV)
Go:github.com/mattermost/mattermost/server/v88.0.0-20250731063404-9eebaadf8f72Package registry (OSV)
opensuse:govulncheck-vulndb0.0.20250917T170349-1.1 · openSUSE:TumbleweedPackage 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.

Variant candidates

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

  • CVE-2025-90840 days apartOpen redirect in OAuth login
    24Monitor
  • CVE-2025-6269093 days apartOpen redirect in error page when link opened in new tab
    24Monitor

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

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
low · data can be read
Integrity
low · data or configuration can be modified
Availability
none

Impact can extend beyond the vulnerable component (scope changes).

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

Weakness class (CWE)

CWE-601 · URL Redirection to Untrusted Site ('Open Redirect')

CVSS vector

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

nvd-primary

Attack context

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

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

  1. Fix✗ → ✓

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

References

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

All records