CVE-2026-91095

MEDIUMPre-NVD 5.35.3—
EchelonGraph scoreHIGH confidence

Score 5.3 from GitHub Security Advisory published 2026-09-28. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 5 sources updated this week
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 5.3Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

In proxygen from v2024.10.28.00 until v2026.09.28.00, the HTTPTransaction::onWebTransportUniStream and HTTPTransaction::onWebTransportBidiStream APIs could return stream handles that the stream handler had already freed. HQSession then installed those handles as transport read callbacks, which could lead to use of freed memory.

CVSS v3
5.3
EG Score
5.3MEDIUMhigh confidence
EG Risk
39
EG Risk 39/100CISA SSVC

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
Severity53% × 45%
Exploitation0% × 40%
Automatability100% × 15%
CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.2%
EPSS %ILE
14th
KEV
Not listed

CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

September 28, 2026

Last Modified

September 30, 2026

Advisory Details (2)

Auto-updated Sep 30, 2026
Patch available. Sources: github_commit.
generic

CVE-2026-91095

https://www.facebook.com/security/advisories/cve-2026-91095
github_commit Patch Available

commit 479eb5574195 (facebook/proxygen)

Patch available: facebook/proxygen v2026.09.28.00 (contains commit 479eb5574195)

https://github.com/facebook/proxygen/commit/479eb5574195764e80e6cedebef669f6baa85083

Vendor Advisories for CVE-2026-91095(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. 2026-10-05 09:41 UTCEG score recompute
  2. 2026-10-05 09:41 UTCGHSA enrichment
  3. 2026-10-04 23:22 UTCEPSS rescore
  4. 2026-10-04 11:51 UTCEG score recompute
  5. 2026-10-04 11:51 UTCGHSA enrichment
  6. 2026-10-03 14:01 UTCEG score recompute
  7. 2026-10-03 14:01 UTCGHSA enrichment
  8. 2026-10-02 16:08 UTCEG score recompute
  9. 2026-10-02 16:08 UTCGHSA enrichment
  10. 2026-10-01 19:51 UTCEPSS rescore
  11. 2026-10-01 18:18 UTCEG score recompute
  12. 2026-10-01 18:17 UTCGHSA enrichment
  13. 2026-09-30 20:23 UTCGHSA enrichment
  14. 2026-09-30 19:56 UTCEG score recompute▲ 5.30
  15. 2026-09-30 19:56 UTCGHSA enrichment
  16. 2026-09-30 19:55 UTCMITRE cvelistV5CVSS v3 → 5.3 · severity → MEDIUM
  17. 2026-09-30 15:04 UTCEPSS rescore
  18. 2026-09-28 21:18 UTCNVD update
  19. 2026-09-28 20:46 UTCEG score recompute
  20. 2026-09-28 20:46 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-91095?
CVE-2026-91095 is a medium vulnerability published on September 28, 2026. In proxygen from v2024.10.28.00 until v2026.09.28.00, the HTTPTransaction::onWebTransportUniStream and HTTPTransaction::onWebTransportBidiStream APIs could return stream handles that the stream handler had already freed. HQSession then installed those handles as transport read callbacks, which…
When was CVE-2026-91095 disclosed?
CVE-2026-91095 was first published on September 28, 2026, with the most recent update on September 30, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-91095 actively exploited?
CVE-2026-91095 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (14th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-91095?
CVE-2026-91095 has a CVSS v3.1 base score of 5.3 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-91095?
A fix for CVE-2026-91095 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-91095 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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