CVE-2026-10103

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreHIGH confidence

Score 4.3 from GitHub Security Advisory published 2026-07-13. a secondary CVSS source baseline 4.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 4 sources updated this week
4.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify post ownership in the shared channel inbound sync handler, which allows an authenticated remote cluster to modify or delete posts authored by local users or other remotes via crafted sync messages referencing arbitrary post IDs in channels shared with that remote.. Mattermost Advisory ID: MMSA-2026-00689

CVSS v3
4.3
EG Score
4.3(high)
EPSS
4.1%
KEV
Not listed

Published

July 13, 2026

Last Modified

July 14, 2026

Advisory Details (1)

Auto-updated Jul 13, 2026
No patch confirmed yet.
generic

Security Updates

https://mattermost.com/security-updates

Vendor Advisories for CVE-2026-10103(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 9× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 16:57 UTCEPSS rescore
  2. 2026-07-15 10:11 UTCEG score recompute
  3. 2026-07-15 10:11 UTCGHSA enrichment
  4. 2026-07-15 02:00 UTCEPSS rescore
  5. 2026-07-14 09:27 UTCEG score recompute
  6. 2026-07-14 09:27 UTCGHSA enrichment
  7. 2026-07-13 22:30 UTCEPSS rescore
  8. 2026-07-13 08:44 UTCEG score recompute
  9. 2026-07-13 08:42 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-10103?
CVE-2026-10103 is a medium vulnerability published on July 13, 2026. Mattermost versions 11.7.x <= 11.7.2, 11.6.x <= 11.6.4, 10.11.x <= 10.11.19 fail to verify post ownership in the shared channel inbound sync handler, which allows an authenticated remote cluster to modify or delete posts authored by local users or other remotes via crafted sync messages referencing…
When was CVE-2026-10103 disclosed?
CVE-2026-10103 was first published in the National Vulnerability Database on July 13, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-10103 actively exploited?
CVE-2026-10103 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 4.1% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-10103?
CVE-2026-10103 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-10103?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-10103, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-10103

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