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01 Record

CVE-2026-25783

Denial of service via malformed User-Agent header in getBrowserVersion

MediumPUBLISHEDCNA: Mattermost
CNA base score4.3 CVSS v3.xCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

02 Description

Denial of service via malformed User-Agent header in getBrowserVersion

03 Exploitation and scoring

Exploitation
Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
SSVC decision
  • ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
  • AutomatablenoAt least one step from reconnaissance to exploitation cannot be reliably automated.
  • Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
CISA publishes the decision points, not a final SSVC decision. The decision also depends on mission and well-being impact, which is a property of your deployment rather than of the vulnerability.
EPSS probability
0.29% probability of exploitation activity in the next 30 days.
EPSS percentile
Equal to or higher than the score of 22.0% of scored records. A rank, not a probability.
NVD base score
4.3 (CVSS v3.x), scored by the NVD independently of the CNA.
NVD CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
NVD analysis status
Analyzed. NVD last modified this record on 2026-06-17.
Red Hat severity
No Red Hat rating. Red Hat rates the CVEs that affect its products.

Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.

04 Metadata

Published
2026-03-16 12:04Z7 MO AGO
Last updated
2026-03-16 13:49Z7 MO AGO
Reserved
2026-02-13
Assigning CNA
Mattermost
Record state
PUBLISHED
Severity
Medium (CVSS 4.3)
CNA CVSS vector
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
Weaknesses
  • CWE-1287Improper Validation of Specified Type of InputBase
Data version
5.2
Document digest
eceda35adfa8cf6d1ddb6174f69fdcbcd2e9037caaff113fe94dd90b7a429a45

05 Affected products

VendorProductVersionsPlatforms
MattermostMattermost11.3.0 to 11.3.0, 11.2.0 to 11.2.2, 10.11.0 to 10.11.10—

06 References

07 Remediation

Update Mattermost to versions 11.4.0, 11.3.1, 11.2.3, 10.11.11 or higher.