CVE-2026-76239

MEDIUMPre-NVD 6.36.3—
EchelonGraph scoreHIGH confidence

Score 6.3 from GitHub Security Advisory published 2026-08-19. a secondary CVSS source baseline 6.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: ghsa, secondary
Trending — 4 sources updated this weekElevated
6.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.3Exploit: Elevated riskExposed: 0

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

Stigmem before 0.9.0a11 fails to validate the delivery_address parameter when creating webhook subscriptions, allowing authenticated users to specify internal loopback and private network destinations. Attackers can trigger matching fact-change events to cause the Stigmem server to issue server-side HTTP POST requests to internal services, enabling blind SSRF attacks against localhost and private network endpoints.

CVSS v3
6.3
EG Score
6.3(high)
EG Risk
44(Track)
EG Risk 44/100SSVC: Track

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
Severity63% × 45%
Exploitation40% × 40%
Automatability0% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
0%
EPSS %ILE
19%
KEV
Not listed

Published

August 19, 2026

Last Modified

August 19, 2026

Advisory Details (2)

Auto-updated Aug 19, 2026
🔬 Proof of concept available. Patch available. Sources: github.
generic

Stigmem before 0.9.0a11 SSRF via unvalidated webhook delivery_address | Advisories | VulnCheck

https://www.vulncheck.com/advisories/stigmem-before-0a11-ssrf-via-unvalidated-webhook-delivery-address
github Patch Available🟡 PoC Available

Blind SSRF via unvalidated webhook subscription delivery_address · Advisory · eidetic-labs/stigmem · GitHub

https://github.com/eidetic-labs/stigmem/security/advisories/GHSA-5p3m-vhh6-9236

Vendor Advisories for CVE-2026-76239(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 8× in last 7d / 8× 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. 2026-08-20 22:56 UTCEPSS rescore
  2. 2026-08-20 14:00 UTCEG score recompute
  3. 2026-08-20 14:00 UTCGHSA enrichment
  4. 2026-08-19 15:24 UTCEG score recompute
  5. 2026-08-19 14:57 UTCEG score recompute
  6. 2026-08-19 14:26 UTCEG score recompute
  7. 2026-08-19 14:12 UTCEG score recompute
  8. 2026-08-19 14:12 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-76239?
CVE-2026-76239 is a medium vulnerability published on August 19, 2026. Stigmem before 0.9.0a11 fails to validate the delivery_address parameter when creating webhook subscriptions, allowing authenticated users to specify internal loopback and private network destinations. Attackers can trigger matching fact-change events to cause the Stigmem server to issue…
When was CVE-2026-76239 disclosed?
CVE-2026-76239 was first published in the National Vulnerability Database on August 19, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-76239 actively exploited?
CVE-2026-76239 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 81.4% of all scored CVEs.
What is the CVSS score of CVE-2026-76239?
CVE-2026-76239 has a CVSS v3 base score of 6.3 (NVD).
How do I remediate CVE-2026-76239?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-76239, 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-2026-76239

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