Is there a public exploit for CVE-2026-128021?

No public exploit for CVE-2026-128021 was found in Exploit-DB, Metasploit, Nuclei templates or public proof-of-concept repositories. That is an absence of evidence rather than proof that none exists.

How severe is CVE-2026-128021?

CVE-2026-128021 scores CVSS 6.3 (v4.0), rated medium.

What does CVE-2026-128021 affect?

CVE-2026-128021 affects PHP frankenphp.

6.3 Medium

FrankenPHP before 1.13.2 contains an information disclosure vulnerability that allows later clients to read earlier clients' libxml errors…

CVE-2026-128021

FrankenPHP before 1.13.2 contains an information disclosure vulnerability that allows later clients to read earlier clients' libxml errors because worker mode never resets LIBXML(errorlist) between requests. Attackers sending requests to the same worker thread can call libxmlgeterrors() or libxmlgetlasterror() to obtain other clients' parsed-document fragments and server filesystem paths.

Assessment

CVSS: 6.3 (v4.0)
Severity: Medium
Known exploited: Not listed in CISA KEV
Exploit availability: Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
Published: 13 November 2026
Last updated: 13 November 2026
Affected: PHP · frankenphp
Assigner: VulnCheck

CVSS vectorCVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N

At the source

EUVD (ENISA)

References

Community proofs of concept

No community proof of concept yet. If you have one for a published vulnerability and the right to share it, add it below — it will appear here once reviewed.

Submit a proof of concept

Only for publicly disclosed vulnerabilities, and only material from testing you were authorised to perform. This platform does not buy, sell, or broker exploits — see earning from vulnerability research for legitimate bounty programs. Submissions are reviewed before they appear. Text only; do not include live credentials, personal data, or anything targeting systems you are not permitted to test.

Title *

Proof of concept *

Write-up (optional)

Affected versions (optional)

Name or handle (optional)

References (optional, one URL per line)

Licence for your contribution *

Private contact (optional, never shown)

Before you submit * This vulnerability is already publicly disclosed (it has a published CVE). This material comes only from testing I was authorised to perform. I have the legal right to publish this content and am not breaching any agreement by doing so. It contains no live credentials, personal data, or anything targeting systems I am not authorised to test. I understand it will be reviewed before it appears publicly and may be rejected. I agree to the submission terms.

What is 6 + 6? *

Query this programmatically

Agents can read this through the MCP endpoint, or over HTTP:

curl https://cve.zerocrew.in/api/cve/CVE-2026-128021