CVE-2026-81421

HIGHPre-NVD 7.37.3—
EchelonGraph scoreHIGH confidence

Score 7.3 from GitHub Security Advisory published 2026-08-27. a secondary CVSS source baseline 7.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — 5 sources updated this weekElevated
7.3EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 7.3Exploit: Elevated riskExposed: 0

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

A security flaw has been discovered in ddfourtwo sentry-selfhosted-mcp 0.4.0. The affected element is an unknown function of the component raw_sentry_api. The manipulation of the argument endpoint results in server-side request forgery. It is possible to launch the attack remotely. The exploit has been released to the public and may be used for attacks. The project was informed of the problem early through an issue report but has not responded yet.

CVSS v3
7.3
EG Score
7.3(high)
EG Risk
64(Attend)
EG Risk 64/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity73% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
21%
KEV
Not listed

Published

August 26, 2026

Last Modified

August 28, 2026

Advisory Details (2)

Auto-updated Aug 27, 2026
🔬 Proof of concept available. No patch confirmed yet.
generic

GitHub - ddfourtwo/sentry-selfhosted-mcp: An MCP server for self-hosted sentry. · GitHub

https://github.com/ddfourtwo/sentry-selfhosted-mcp/
generic🟡 PoC Available

Server-Side Request Forgery Vulnerability in sentry-selfhosted-mcp · Issue #2 · ddfourtwo/sentry-selfhosted-mcp · GitHub

https://github.com/ddfourtwo/sentry-selfhosted-mcp/issues/2

Vendor Advisories for CVE-2026-81421(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 20× in last 7d / 20× 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. 2026-08-30 06:41 UTCEG score recompute
  2. 2026-08-30 06:41 UTCGHSA enrichment
  3. 2026-08-30 01:22 UTCEPSS rescore
  4. 2026-08-29 17:36 UTCGHSA enrichment
  5. 2026-08-29 04:31 UTCEG score recompute
  6. 2026-08-29 04:31 UTCGHSA enrichment
  7. 2026-08-28 21:42 UTCEPSS rescore
  8. 2026-08-28 15:22 UTCGHSA enrichment
  9. 2026-08-28 06:36 UTCGHSA enrichment
  10. 2026-08-27 17:29 UTCEG score recompute
  11. 2026-08-27 17:29 UTCGHSA enrichment
  12. 2026-08-27 17:24 UTCNVD updateCVSS v4 → 5.5
  13. 2026-08-27 16:43 UTCMITRE cvelistV5CVSS v4 → 6.9
  14. 2026-08-27 14:27 UTCEG score recompute
  15. 2026-08-27 14:27 UTCGHSA enrichment
  16. 2026-08-27 14:25 UTCEPSS rescore
  17. 2026-08-27 01:22 UTCEG score recompute
  18. 2026-08-27 01:21 UTCNVD updateCVSS v4 → 5.5
  19. 2026-08-27 00:22 UTCEG score recompute
  20. 2026-08-27 00:22 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-81421?
CVE-2026-81421 is a high vulnerability published on August 26, 2026. A security flaw has been discovered in ddfourtwo sentry-selfhosted-mcp 0.4.0. The affected element is an unknown function of the component rawsentryapi. The manipulation of the argument endpoint results in server-side request forgery. It is possible to launch the attack remotely. The exploit has…
When was CVE-2026-81421 disclosed?
CVE-2026-81421 was first published in the National Vulnerability Database on August 26, 2026, with the most recent update on August 28, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-81421 actively exploited?
CVE-2026-81421 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 79.1% of all scored CVEs.
What is the CVSS score of CVE-2026-81421?
CVE-2026-81421 has a CVSS v3 base score of 7.3 (NVD).
How do I remediate CVE-2026-81421?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-81421, 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

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