High

HTTP Request Smuggling in Apache Tomcat via Invalid Chunk Extension

IdentifiersCVE-2026-24880CWE-444· Inconsistent Interpretation of…

CVE-2026-24880 is an HTTP request/response smuggling vulnerability in Apache Tomcat caused by inconsistent interpretation of HTTP requests when processing an invalid chunk extension in chunked transfer encoding. Apache identifies the issue as an Inconsistent Interpretation of HTTP Requests weakness. Affected versions are Tomcat 11.0.0-M1 through 11.0.18, 10.1.0-M1 through 10.1.52, 9.0.0.M1 through 9.0.115, 8.5.0 through 8.5.100, and 7.0.0 through 7.0.109; unsupported versions may also be affected. The flaw can arise when Tomcat and another HTTP component in the request path interpret malformed chunked requests differently, enabling request boundary desynchronization.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can enable HTTP request/response smuggling across a proxy-to-origin or intermediary-to-Tomcat chain. Depending on deployment architecture, this may allow an attacker to bypass front-end security controls, poison shared caches, interfere with request routing, cause users to receive unintended responses, or access responses associated with other users' requests. Third-party advisories also note possible downstream effects including denial of service, authentication bypass, or disclosure of sensitive information in affected products that embed vulnerable Tomcat versions.

Mitigation

If you can’t patch tonight, do this now.

No specific workaround is provided in the supplied content. Practical mitigation is to reduce or eliminate exposure to request desynchronization conditions until patching is completed, including ensuring consistent HTTP parsing behavior across reverse proxies and Tomcat, scrutinizing handling of chunked transfer encoding, and limiting direct exposure of affected Tomcat instances. However, the authoritative remediation in the provided material is to upgrade.

Remediation

Patch, then assume compromise.

Upgrade Apache Tomcat to a fixed release. Apache recommends upgrading to Tomcat 11.0.20, 10.1.53, or 9.0.116. Older affected branches such as 8.5.x and 7.0.x should be moved to a supported fixed version where possible. Debian product advisories additionally provide distribution-specific fixed package versions, including tomcat10 10.1.55-1~deb12u1 or 10.1.55-1~deb13u1, and tomcat11 11.0.22-1~deb13u1 or later.

PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

EXPOSURE SURFACE

Affected products & vendors

Products and vendors Mallory has correlated with this vulnerability. Open in Mallory to drill down to specific CPE configurations and version ranges.

VendorProductType

Apache Software FoundationTomcatapplication

Apache Software FoundationTomcat-Coyoteapplication

Apache Software FoundationTomcat-Embed-Coreapplication

Apache Software FoundationTomcat-Tribesapplication

F5Traffix Sdcapplication

Vendor-confirmed product mapping. Mallory continuously reconciles this list against your asset inventory.

ACTIVITY FEED

Recent activity

11 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

11 SOURCESView more in app

atlassian confluenceNews

May 19, 2026

Security Bulletin - May 19 2026 | Atlassian Support | Atlassian Documentation

An HTTP request/response smuggling vulnerability in an Apache Tomcat dependency affecting Confluence Data Center.

atlassian confluenceNews

Apr 22, 2026

Security Bulletin - April 21 2026 | Atlassian Support | Atlassian Documentation

HTTP request smuggling vulnerability in the org.apache.tomcat:tomcat-catalina dependency affecting Bamboo Data Center.

What this page doesn’t show

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Exposure mapping

Query your assets running an affected version, and investigate the blast radius.

Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity6