CVE-2025-59039: Prebid-universal-creative latest on npm briefly compromised

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.3%, percentile 26: FIRST’s model estimates a 0.3% chance of exploitation activity in the next 30 days, higher than 26% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes prebid-universal-creative (npm) = 1.17.3, no fixed version listed. Check your lockfile, including transitive dependencies.

What it is

Prebid Universal Creative (PUC) is a JavaScript API to render multiple formats. Npm users of PUC 1.17.3 or PUC latest were briefly affected by crypto-related malware. This includes the extremely popular jsdelivr hosting of this file. The maintainers of PUC unpublished version 1.17.3. Users should see Prebid.js 9 release notes for suggestions on moving off the deprecated workflow of using the PUC or pointing to a dynamic version of it. PUC users pointing to latest should transition to 1.17.2 as soon as possible to avoid similar attacks in the future.

From the GitHub advisory

Impact Npm users of PUC 1.17.3 or PUC latest were briefly affected by crypto-related malware detailed in the blog post below. This includes the extremely popular jsdelivr hosting of this file.

Patches We unpublished the version on npm.

Workarounds This has already been unpublished. See Prebid.js 9 release notes for suggestions on moving off the deprecated workflow of using the PUC or pointing to a dynamic version of it. PUC users pointing to latest should transition to 1.17.2 ASAP to avoid similar attacks in the future.

References https://www.sonatype.com/blog/npm-chalk-and-debug-packages-hit-in-software-supply-chain-attack

Weakness type: CWE-506.

Product: prebid-universal-creative (npm) · Assigned by: GitHub_M · Published: 2025-09-09

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.34% probability of exploitation activity in the next 30 days; percentile 26.

Timeline

• 2025-09-09 — CVE record published by GitHub_M
• 2025-09-10 — CVE record last updated
• 2025-09-11 — GitHub-reviewed advisory GHSA-m662-56rj-8fmm published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-m662-56rj-8fmm github.com
2. CVE.org record CVE-2025-59039 cve.org
3. NVD entry CVE-2025-59039 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. sonatype.com sonatype.com

Critical npm advisories · Today’s Security Digest