Unrated

Bad ornext processing in Apache Tomcat RewriteValve

IdentifiersCVE-2026-53404CWE-670

CVE-2026-53404 is a low-severity vulnerability in Apache Tomcat's RewriteValve component. The flaw is described as an always-incorrect control flow implementation issue in rewrite rule condition evaluation: when processing an OR chain, if the first condition matched, subsequent non-OR conditions were incorrectly skipped. This causes RewriteValve to evaluate rule logic differently than intended, potentially allowing rewrite rules and any security decisions embedded in those rules to be applied incorrectly. Affected versions are Apache Tomcat 11.0.0-M1 through 11.0.22, 10.1.0-M1 through 10.1.55, 9.0.0.M1 through 9.0.118, and 8.5.0 through 8.5.100. Other end-of-support versions may also be affected.

For your environment

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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.

The primary impact is security restriction bypass or policy bypass where administrators rely on RewriteValve conditions to enforce access control, request filtering, or other security-sensitive routing logic. Because subsequent non-OR conditions may be skipped after the first OR condition matches, requests that should have failed the full condition set may instead satisfy the rule path and receive unintended handling. Depending on deployment-specific rewrite rules, this could enable unauthorized access to protected paths or weaken request validation. The provided context does not establish direct code execution from this flaw.

Mitigation

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

If immediate upgrade is not possible, review all RewriteValve rules that use OR-chained conditions and assume their evaluation may be unsafe on affected versions. Avoid relying on RewriteValve alone for security-critical access restrictions until patched. Where feasible, enforce equivalent controls in the application, container security constraints, reverse proxy, or upstream WAF/load balancer so that access decisions do not depend solely on vulnerable rewrite-condition processing.

Remediation

Patch, then assume compromise.

Upgrade Apache Tomcat to a fixed release: 11.0.23, 10.1.56, or 9.0.119. For 8.5.x, the content identifies affected versions through 8.5.100 but does not provide a fixed 8.5.x release in the supplied material. Organizations running unsupported or end-of-support Tomcat branches should migrate to a supported fixed version, as those versions may also be affected.

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

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

ACTIVITY FEED

Recent activity

8 sources tracked across advisories and community write-ups. News coverage will land here when it surfaces.

8 SOURCESView more in app

No news coverage yet. Advisories and community discussion only.

What this page doesn’t show

The version that knows your environment.

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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 activity7

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES

MITRE CVE

cve.org · CVE-2026-53404

NVD

nvd.nist.gov/vuln/detail/CVE-2026-53404

MITRE CWE · CWE-670

cwe.mitre.org