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Vulnerabilities

Vulnerability · CVE-2026-118664

decode-uri-component vulnerable to denial of service via quadratic replacement of percent-encoded runs

Published Oct 29, 2026 · catalog updated Oct 29, 2026 · decode-uri-component vulnerable to denial

Last checked Nov 5, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-118664. EPSS is 0.32%. Act only if a listed version of decode-uri-component vulnerable to denial is installed.

Gaps on this record

  • The stored product name is a package slug. The name on this page is taken from the title (decode-uri-component vulnerable to denial).
  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High—
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.32%
Remediation
Version ranges on file
Affected products
npm decode-uri-component

### Summary takes quadratic time on malformed input that has many distinct percent-encoded runs. A single unauthenticated request of about 224 KB can block the Node.js event loop for about 20 seconds. Version 0.5.0, the release that fixed CVE-2026-45822, is affected. ### Details When native decodeURIComponent throws, falls back to ( ). That function: 1. Scans the input for every run of percent-encoded bytes (e.g. ) and stores each distinct run, with its decoded value, in a lookup table ( ). 2. Runs one full-string per table entry ( ). With K distinct runs in an input of length L, that's K regex compilations and K full scans of the string, so O(K·L). An attacker controls both K and L, and K grows with L. One malformed sequence such as a trailing is enough to force the fallback path. The 0.5.0 fix for CVE-2026-45822 ( ) replaced the recursive routine with a linear scanner, but left this replacement loop unchanged. ### Proof of concept Running the following code takes ~20 seconds. ### Impact This is an availability issue only and there's no confidentiality or integrity impact. Any application that passes untrusted input to , directly or through a dependency such as , can be made unresponsive. Because Node.js runs on one thread, one request stalls every other client. The worst case needs input well beyond URL length limits. Node's default 16 KB header limit keeps payloads passed in via a URL query string to roughly 40 ms per request. Applications that decode request bodies are fully exposed, for example form bodies parsed with .

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • npm decode-uri-component<0.5.1
  • npm decode-uri-component<= 0.5.0

How to fix CVE-2026-118664

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-118664. EPSS is 0.32%. Act only if a listed version of decode-uri-component vulnerable to denial is installed.

Which versions are affected?

Compare what you have installed with <0.5.1, <= 0.5.0. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

CWE-400: Uncontrolled Resource Consumption; CWE-407. EPSS 0.32%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 29, 2026 · GitHub Advisory Database

    Detected

    ### Summary takes quadratic time on malformed input that has many distinct percent-encoded runs. A single unauthenticated request of about 224 KB can block the Node.js event loop for about 20 seconds. Version 0.5.0, the release that fixed CVE-2026-45822, is affected. ### Details When native decodeURIComponent throws, falls back to ( ). That function: 1. Scans the input for every run of percent-enc

  2. Oct 29, 2026 · GitHub Advisory Database

    Updated

    ### Summary takes quadratic time on malformed input that has many distinct percent-encoded runs. A single unauthenticated request of about 224 KB can block the Node.js event loop for about 20 seconds. Version 0.5.0, the release that fixed CVE-2026-45822, is affected. ### Details When native decodeURIComponent throws, falls back to ( ). That function: 1. Scans the input for every run of percent-enc

Sources

  • CVE.orgVulnerability recordCVE-2026-118664

    Official CVE identifier

    cve.org
  • GitHub Advisory DatabasePackage advisoryGHSA-qr28-fpjm-wq7f

    decode-uri-component vulnerable to denial of service via quadratic replacement of percent-encoded runs

    github.com
  • GitLab Advisory DatabasePackage advisoryCVE-2026-118664

    decodeUriComponent() takes quadratic time on malformed input that has many distinct percent-encoded runs. A single unauthenticated request of about 224 KB can block the Node.js event loop for about 20 seconds. Version 0.5.0, the release that fixed CVE-2026-45822, is affected.

    advisories.gitlab.com
  • GitLab Advisory DatabasePackage advisorynpm/decode-uri-component/CVE-2026-118664.yml

    takes quadratic time on malformed input that + has many distinct percent-encoded runs. A single unauthenticated request of about + 224 KB can block the Node.js event loop for about 20 seconds. Version 0.5.0, the + release that fixed CVE-2026-45822, is affected." +date: "2026-10-29" +pubdate: "2026-10-29" +affected_range: "<0.5.1" +fixed_versions: +- "0.5.1" +affected_versions: "All versions before

    gitlab.com

References

Freshness

Last verified in this catalog Nov 5, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • GitLab Advisory DatabaseNov 3, 2026
  • CVE.orgOct 30, 2026
  • GitLab Advisory DatabaseOct 30, 2026
  • GitHub Advisory DatabaseOct 30, 2026