# CVE-2026-128021: FrankenPHP before 1.13.2 Information Disclosure via libxml Error State in Worker Mode

Status: published. Published: 2026-11-13. Updated: 2026-11-13.

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(error_list) between requests. Attackers sending requests to the same worker thread can call libxml_get_errors() or libxml_get_last_error() to obtain other clients' parsed-document fragments and server filesystem paths.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- php / frankenphp (github.com/dunglas/frankenphp): ≥ 0; < 1.13.2 (affected, semver); 1.13.2 (unaffected, semver). Source: CNA: VulnCheck

## Severity and prioritization

- CVSS 4.0: 6.3 (medium); CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N; source: CNA: VulnCheck

- CVSS 3.1: 3.7 (low); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N; source: CNA: VulnCheck

- CVSS 4.0: 6.3 (medium); CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X; source: NVD: disclosure@vulncheck.com

- CVSS 3.1: 3.7 (low); CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N; source: NVD: disclosure@vulncheck.com

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: Not available

- Weaknesses: CWE-200

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://github.com/php/frankenphp/security/advisories/GHSA-4gfw-9v29-gp9h (CNA: VulnCheck; vendor-advisory)

- https://www.vulncheck.com/advisories/frankenphp-before-1.13.2-information-disclosure-via-libxml-error-state-in-worker-mode (CNA: VulnCheck; third-party-advisory)

- https://github.com/php/frankenphp/security/advisories/GHSA-4gfw-9v29-gp9h (disclosure@vulncheck.com)

- https://www.vulncheck.com/advisories/frankenphp-before-1.13.2-information-disclosure-via-libxml-error-state-in-worker-mode (disclosure@vulncheck.com)

## Provenance

- CNA: VulnCheck: https://www.cve.org/CVERecord?id=CVE-2026-128021; retrieved 2026-11-13; source updated 2026-11-13

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-128021; retrieved 2026-11-13; source updated 2026-11-13

Revision: 1c3ae758cfa3f468b0097318fe9dc9a5891c4173b3ddd7eef32a2b9b456cac1e

Canonical: https://y2.dev/cve/CVE-2026-128021

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