decode-uri-component: Denial of service via exponential decoding of malformed percent-encoded input

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS 4.0

6.6 · CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/S:N/AU:Y/R:U/V:D/RE:M/U:Amber · score source

EPSS

• CVE-2026-45822: 0.51% estimated exploitation activity in the next 30 days; percentile 43.30 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Impact An attacker who can supply input to decodeUriComponent() (directly or via a dependency that uses this package on URL/query/path data) can cause excessive CPU usage and application unresponsiveness. This is an availability issue; there is no known memory corruption, data disclosure, or remote code execution impact. Patches Upgrade to decode-uri-component@0.5.0. Workarounds Limit the size of the input.

Published by the source

31 Aug 2026, 22:10 UTC

Last modified by the source

31 Aug 2026, 22:10 UTC

Source last checked

26 Oct 2026, 13:01 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-vcc3-ghjq-m6fr

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# Patch Next advisory brief: CVE-2026-45822

Advisory: decode-uri-component: Denial of service via exponential decoding of malformed percent-encoded input
IDs: CVE-2026-45822, GHSA-vcc3-ghjq-m6fr
Record: https://patchnext.com/advisories/cve-2026-45822 (revision 1, source checked 26 Oct 2026, 13:01 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: Medium (CVSS 6.6)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: decode-uri-component 0.5.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- npm decode-uri-component: affected <= 0.4.2; fixed in 0.5.0

## Suggested inspection (read-only)
- `npm ls decode-uri-component --all`: lists every installed copy and version, including transitive ones. Run in the project root after `npm ci`.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on decode-uri-component.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-vcc3-ghjq-m6fr (GitHub-reviewed advisory GHSA-vcc3-ghjq-m6fr lists affected ranges: npm decode-uri-component >=0 <=0.4.2)

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