High

ReDoS in method-override X-HTTP-Method-Override header parsing

IdentifiersCVE-2017-16136CWE-1333

CVE-2017-16136 is a regular expression denial of service (ReDoS) vulnerability in the Node.js method-override module used with Express.js applications. The flaw is triggered when specially crafted, untrusted input supplied via the X-HTTP-Method-Override header is parsed by the module, causing excessive backtracking or otherwise expensive regular expression evaluation. This can consume disproportionate CPU resources during request processing and degrade application responsiveness.

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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.

A remote attacker can send crafted HTTP requests containing a malicious X-HTTP-Method-Override header value that causes excessive regular expression processing in the vulnerable method-override module. Successful exploitation can tie up server CPU resources and lead to denial of service, slowing or preventing legitimate requests from being processed.

Mitigation

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

If immediate patching is not possible, reduce exposure by disabling or restricting use of the X-HTTP-Method-Override header where not strictly required, filtering or validating header values before they reach the module, and applying request rate limiting or upstream protections to reduce the impact of malicious repeated requests. These measures are compensating controls and do not replace upgrading to a fixed version.

Remediation

Patch, then assume compromise.

Upgrade method-override to version 2.3.10 or later, which addresses the vulnerable header parsing behavior. Ensure dependent Express.js applications resolve and deploy the patched package version in production environments.

PUBLIC EXPLOITS

Exploits

No valid public exploits. Mallory filtered out 2 candidates as fakes, detection scripts, or README-only repos.

VALID 0 / 2 TOTALView more in app

All candidate exploits were filtered out by Mallory's validation.

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

ExpressjsMethod-Overrideapplication

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

ACTIVITY FEED

Recent activity

No public activity tracked yet. Mallory keeps watching.

0 SOURCESView more in app

No public activity observed for this vulnerability.

What this page doesn’t show

The version that knows your environment.

This page is what’s public. Mallory adds the parts that aren’t: which of your assets are affected, which adversaries are exploiting it right now, which detections to deploy, and what to do tonight.

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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 activity