CVE-2023-26139: Versions of the package underscore-keypath from 0.0.11 are vulnerable to Prototype Pollution via the name argu

Q: How do I fix CVE-2023-26139?

underscore-keypath: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Q: Is CVE-2023-26139 being exploited?

CVE-2023-26139 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-2023-26139 affect?

CVE-2023-26139 affects underscore-keypath. Severity is high (CVSS 7.5). Versions of the package underscore-keypath from 0.0.11 are vulnerable to Prototype Pollution via the name argument of the setProperty() function. Exploiting this vulnerability is possible due to improper input sanitization which allows the

Q: How urgent is CVE-2023-26139?

Priority 46/100. High severity; Remotely exploitable, no login, no user action

This month

HIGH 7.5REMOTEDOWNGRADE

CVE-2023-26139 is a high-severity flaw (CVSS 7.5) affecting underscore-keypath. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Versions of the package underscore-keypath from 0.0.11 are vulnerable to Prototype Pollution via the name argument of the setProperty() function. Exploiting this vulnerability is possible due to improper input sanitization which allows the usage of arguments like “__proto__”.

Why this priority

High severity
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.9% (top 41%)
CISA exploited list	No
Weakness	CWE-1321
Published	2023-08-01
Last modified	2026-06-17

Publisher (CNA): Snyk · Vendor: underscore-keypath project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-08-01 05:15 UTCPublished CVE record published
2026-06-17 05:42 UTCUpdated Record last modified

underscore-keypath project underscore-keypath DOWNGRADE

Affected: >= 0.0.11

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.0.11

1. Check installed version

npm ls underscore-keypath

2. No fixed release: DOWNGRADE to a release before 0.0.11

npm view underscore-keypath versions npm install underscore-keypath@"<0.0.11"

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-2023-26139?

underscore-keypath: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-26139 being exploited?

CVE-2023-26139 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-2023-26139 affect?

CVE-2023-26139 affects underscore-keypath. Severity is high (CVSS 7.5). Versions of the package underscore-keypath from 0.0.11 are vulnerable to Prototype Pollution via the name argument of the setProperty() function. Exploiting this vulnerability is possible due to improper input sanitization which allows the

How urgent is CVE-2023-26139?

Priority 46/100. High severity; Remotely exploitable, no login, no user action

References

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