CVE-2026-77756

LOWPre-NVD 3.73.7—
EchelonGraph scoreHIGH confidence

Score 3.7 from GitHub Security Advisory (severity: LOW) published 2026-09-23. CISA-ADP (Vulnrichment) CVSS v3.1 baseline 3.7; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: cisa-adp, epss, ghsa
Trending — 4 sources updated this week
3.7EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 3.7Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from another user to fail when Tomcat is located behind a reverse proxy.

This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.47 through 9.0.121.

The following versions were EOL at the time the CVE was created but are known to be affected: from 8.5.67 through 8.5.100. Other unsupported versions may also be affected.

Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.

CVSS v3
3.7
EG Score
3.7LOWhigh confidence
EG Risk
17
EG Risk 17/100CISA 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
Severity37% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
15th
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (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 23, 2026

Last Modified

September 23, 2026

References (2)

Vendor Advisories for CVE-2026-77756(3)

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

Patch Availability(2)

Vendor / EcosystemFixed in / PatchReleasedSource
redhattomcat10-main-10.1.60-0.1.hum12026-09-16redhat
redhattomcat11-main-11.0.26-0.1.hum12026-09-16redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 11× in last 7d / 27× 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. 2026-10-03 14:26 UTCEPSS rescore
  2. 2026-10-03 13:10 UTCEG score recompute
  3. 2026-10-03 13:10 UTCVendor advisory
  4. 2026-10-03 13:10 UTCGHSA enrichment
  5. 2026-10-01 19:50 UTCEPSS rescore
  6. 2026-09-30 07:18 UTCEG score recompute
  7. 2026-09-30 07:18 UTCVendor advisory
  8. 2026-09-30 07:18 UTCGHSA enrichment
  9. 2026-09-29 15:24 UTCEPSS rescore
  10. 2026-09-28 13:52 UTCEPSS rescore
  11. 2026-09-27 13:48 UTCEPSS rescore
  12. 2026-09-27 01:26 UTCEG score recompute
  13. 2026-09-27 01:25 UTCGHSA enrichment
  14. 2026-09-26 15:59 UTCEPSS rescore
  15. 2026-09-26 00:28 UTCEPSS rescore
  16. 2026-09-24 14:04 UTCEPSS rescore
  17. 2026-09-23 19:30 UTCGHSA enrichment
  18. 2026-09-23 18:23 UTCGHSA enrichment
  19. 2026-09-23 18:00 UTCEG score recompute
  20. 2026-09-23 17:59 UTCGHSA enrichment
  21. 2026-09-23 14:36 UTCGHSA enrichment
  22. 2026-09-23 13:26 UTCEG score recompute▲ 3.70
  23. 2026-09-23 13:26 UTCGHSA enrichment
  24. 2026-09-23 13:25 UTCMITRE cvelistV5CVSS v3 → 3.7 · severity → LOW
  25. 2026-09-23 12:29 UTCNVD update
Show 2 more
  1. 2026-09-23 11:21 UTCEG score recompute
  2. 2026-09-23 11:21 UTCMITRE cvelistV5first tracked

Related CVEs(same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-77756?
CVE-2026-77756 is a low vulnerability published on September 23, 2026. Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling') vulnerability in Apache Tomcat caused by processing the transfer-encoding header for an HTTP/1.0 request may allow an attacker to cause one request from another user to fail when Tomcat is located behind a reverse…
When was CVE-2026-77756 disclosed?
CVE-2026-77756 was first published on September 23, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-77756 actively exploited?
CVE-2026-77756 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (15th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-77756?
CVE-2026-77756 has a CVSS v3.1 base score of 3.7 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-77756?
A fix for CVE-2026-77756 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-77756 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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