CVE-2026-77756

Description

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.

Overview

State: PUBLISHED
Assigner (CNA): apache
CVSS severity: —
CVSS score: —
CVSS vector: —
Effective score: 3.7 / 10 LOW source: NVD
CWE(s): CWE-444
Reserved: 2026-08-21
Published: 2026-09-23 11:18 UTC
Last updated: 2026-09-23 18:10 UTC
Source: https://raw.githubusercontent.com/CVEProject/cvelistV5/main/cves/2026/77xxx/CVE-2026-77756.json

NVD triage scoring NVD CVE 2.0

Layer NVD adds on top of the CNA's CVE record — published / last-modified timestamps, exploitability / impact subscores, and the FIRST.org EPSS probability that this CVE will be exploited in the wild in the next 30 days.

NVD published: 2026-09-23 12:17:06 UTC
NVD last modified: 2026-09-23 19:19:18 UTC
NVD CVSS v3.1: 3.7 / 10 LOW source: 134c704f-9b21-4f2e-91b3-4a467353bcc0
NVD CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
Exploitability subscore: 2.2 / 10
Impact subscore: 1.4 / 10

European Union Vulnerability Database ENISA EUVD

ENISA's official EU repository for curated vulnerability intelligence. Carries a separate identifier (EUVD-YYYY-NNNN) and frequently exposes an earlier-published description + CVSS than NVD does.

EUVD ID: EUVD-2026-85226
Assigner: apache
Published: Sep 23, 2026, 11:18:02 AM
Updated: Sep 23, 2026, 6:10:42 PM
EUVD base score (CVSS 3.1): 3.7 / 10
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L
EUVD-reported EPSS: 0.0000
Vendors: Apache Software Foundation
Products: Apache Tomcat (11.0.0-M1 ≤11.0.25)

Apache Tomcat (10.1.0-M1 ≤10.1.59)

Apache Tomcat (9.0.47 ≤9.0.121)

Apache Tomcat (8.5.67 ≤8.5.100)
Aliases: GHSA-gpfr-7w77-mp48

ENISA description: 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.

EUVD references (1)

https://lists.apache.org/thread/bl5b6rxqh3vb2k9bj2794vhor7o6xl3z

Affected products (1)

Vendor	Product	Versions	Platforms
Apache Software Foundation	Apache Tomcat	`11.0.0-M1` (affected), `10.1.0-M1` (affected), `9.0.47` (affected), `8.5.67` (affected), `0` (unaffected)	—

Vendor references (1)

References embedded in the original CVE record by the assigning CNA.

https://lists.apache.org/thread/bl5b6rxqh3vb2k9bj2794vhor7o6xl3z vendor-advisory

Web references (0)

DuckDuckGo results ranked by threat-intel / vendor advisory domains. Generated by the 🔎 Find references (web) button above — same flow as the Remediations search.

No web references attached yet.

NVD-tagged references (2)

Reference list NVD curates from the CNA record, vendor advisories, and third-party reports. The tag chips below are NVD's analyst-assigned categories.

http://www.openwall.com/lists/oss-security/2026/09/23/22 af854a3a-2127-422b-91ae-364da2661108
https://lists.apache.org/thread/bl5b6rxqh3vb2k9bj2794vhor7o6xl3z security@apache.org

Remediations (10)

CVE-2026-77756 Apache — Exploit & Vulnerability Details LOW | AnonHaven

web:anonhaven.com

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.

2026-09-24 11:50 UTC
CVE-2026-77756: HTTP Request/Response Smuggling | CVETodo

web:cvetodo.com

CVE-2026-77756 : HTTP Request/Response Smuggling in Apache Tomcat (CVSS 3.7). Full technical analysis, mitigations , and exploit status — updated in real time.

2026-09-24 11:50 UTC
Security Update Guide - Microsoft Security Response Center

web:msrc.microsoft.com

Security Update Guide - Microsoft Security Response Center

2026-09-24 11:50 UTC
CVE-2026-77756: Apache Software Foundation Apache Tomcat…

web:security.glexia.com

CVE-2026-77756 is a vulnerability. Affecting Apache Software Foundation Apache Tomcat. Review impact, affected versions, remediation priorities, CWE and ATT&CK…

2026-09-24 11:50 UTC
CVE-2026-77756 - security-tracker.debian.org

web:security-tracker.debian.org

Vulnerable and fixed packages The table below lists information on source packages.

2026-09-24 11:50 UTC
Microsoft Patch Tracker (September 2026): Exploit-Ranked | Senserva

web:senserva.com

Every Microsoft security patch (KB) and the CVEs it fixes, with severity, CVSS, and CISA KEV status. Cross-linked to the CVE reference.

2026-09-24 11:50 UTC
CVE-2026-50656 ShieldBreak Claims Defender Fix Bypass — Megathread

web:windowsforum.com

ShieldBreak, a newly published proof of concept from the researcher known as Nightmare Eclipse, claims to bypass Microsoft's July fix for the Microsoft Defender privilege-escalation flaw CVE - 2026 -50656, better known as RoguePlanet.

2026-09-24 11:50 UTC
Critical Patches Issued for Microsoft Products, July 14, 2026

web:www.cisecurity.org

Microsoft reports CVE - 2026 -56164 has been exploited in the wild. CVE - 2026 -56164 may allow remote cyber threat actors to gain unauthorized access to on-premises SharePoint Server instances. Microsoft noted that integrating its Antimalware Scan Interface (AMSI) can provide temporary mitigation by actively scanning and detecting malicious POST requests associated with exploitation attempts. The ...

2026-09-24 11:50 UTC
Oracle Critical Patch Update Advisory - July 2026

web:www.oracle.com

This Critical Patch Update contains 1448 new security patches across the product families listed below. Please note that a My Oracle Support (MOS) note summarizing the content of this Critical Patch Update and other Oracle Software Security Assurance activities is located at July 2026 Critical Patch Update: Executive Summary and Analysis.

2026-09-24 11:50 UTC
CVE-2026-77756: Apache Tomcat Vulnerability — Fix & Details

web:www.strix.ai

How severe is CVE-2026-77756 ? Severity scoring for CVE-2026-77756 is pending analysis. How do I fix CVE-2026-77756 ? Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

2026-09-24 11:50 UTC

AI Forensic Analysis

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Raw JSON

The full cvelistV5 record. Download as CVE-2026-77756.json.

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