CVE-2026-75899: fast-uri is a URI parser for Node.js

Q: How do I fix CVE-2026-75899?

fast-uri: upgrade to 2.4.5, 3.1.6, 4.1.3. Exact commands for each OS are on this page.

Q: Is CVE-2026-75899 being exploited?

CVE-2026-75899 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-75899 affect?

CVE-2026-75899 affects fast-uri. Severity is high (CVSS 7.5). fast-uri is a URI parser for Node.js. It decodes percent escapes in a hostname during parsing and then decodes the parsed hostname a second time during authority recomposition, so a single call to normalize or resolve can turn nested percen

Q: How urgent is CVE-2026-75899?

Priority 34/100. High severity; Remotely exploitable, no login, no user action

Routine

HIGH 7.5REMOTEUPGRADE

CVE-2026-75899 is a high-severity flaw (CVSS 7.5) affecting fast-uri. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

fast-uri is a URI parser for Node.js. It decodes percent escapes in a hostname during parsing and then decodes the parsed hostname a second time during authority recomposition, so a single call to normalize or resolve can turn nested percent-encoded input into a different network destination such as a loopback hostname or address. For example, a doubly encoded host that spells out a loopback name decodes to that live host in one operation, which

Why this priority

High severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 88%)
CISA exploited list	No
Weakness	CWE-174, CWE-918
Published	2026-08-24
Last modified	2026-10-14

Publisher (CNA): openjs · Vendor: openjsf

Last updated 2026-10-14 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-08-24 10:16 UTCPublished CVE record published
2026-10-14 13:10 UTCUpdated Record last modified

openjsf fast-uri UPGRADE

Affected: >= 2.4.1 and < 2.4.5 · >= 3.1.2 and < 3.1.6 · >= 4.0.0 and < 4.1.3

Fixed in: 2.4.5, 3.1.6, 4.1.3

Safe to downgrade to: a release before 2.4.1

1. Check installed version

npm ls fast-uri

2. UPGRADE to 2.4.5

npm install fast-uri@">=2.4.5"

3. If no update is available yet, DOWNGRADE to a release before 2.4.1

npm view fast-uri versions npm install fast-uri@"<2.4.1"

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-75899?

fast-uri: upgrade to 2.4.5, 3.1.6, 4.1.3. Exact commands for each OS are on this page.

Is CVE-2026-75899 being exploited?

CVE-2026-75899 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-75899 affect?

CVE-2026-75899 affects fast-uri. Severity is high (CVSS 7.5). fast-uri is a URI parser for Node.js. It decodes percent escapes in a hostname during parsing and then decodes the parsed hostname a second time during authority recomposition, so a single call to normalize or resolve can turn nested percen

How urgent is CVE-2026-75899?

Priority 34/100. High severity; Remotely exploitable, no login, no user action

Software pages

Node.js vulnerabilities

Related CVEs

CVE-2026-75931 HIGH 7.5 UPGRADE fast-uri is a URI parser for Node.js
CVE-2026-76172 HIGH 7.5 UPGRADE fast-uri is a URI parser for Node.js
CVE-2026-75975 HIGH 7.5 UPGRADE fast-uri is a URI parser for Node.js
CVE-2026-84292 HIGH 7.5 UPGRADE fast-uri serializes the port component of a URI without validating it
CVE-2026-84394 HIGH 7.5 DOWNGRADE fast-uri accepts a host that contains an unbalanced or misplaced authority bracket without reporting an error

References

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