01 Record
CVE-2026-86348
MS Calendar plugin: unrecovered handler panics from malformed post-action requests could crash the plugin process
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
MS Calendar plugin: unrecovered handler panics from malformed post-action requests could crash the plugin process
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.
- EPSS probability
- 0.36% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 30.2% 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 2026-10-14.
- 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
- 2026-09-14 13:52Z1 MO AGO
- Last updated
- 2026-09-14 19:23Z1 MO AGO
- Reserved
- 2026-09-07
- 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-704Incorrect Type Conversion or CastClass
- Data version
- 5.2
- Document digest
- 140771bfb7debc23694566161dc37e193108d39b4dcdcf12d284e0cecfb1ad28
05 Affected products
VendorProductVersionsPlatforms
MattermostMattermost<=11.9 11.0.9 11.4.8 11.7.7 10.22.11.0 to <=11.9 11.0.9 11.4.8 11.7.7 10.22.11.0—
06 References
- mattermost.comMMSA-2026-00701https://mattermost.com/security-updates
07 Remediation
Update Mattermost to versions 11.10.0, 11.9.1, 11.8.5, 11.7.8, 10.11.23 or higher.