CVE-2026-42551
CVE-2026-42551 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-436.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- EPSS exploit prediction: 0% (23rd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-30150
- Weakness: CWE-436
- Published:
- Last modified:
Description
Flight is an extensible micro-framework for PHP. Prior to 3.18.1, Request::getMethod() unconditionally honors the X-HTTP-Method-Override header and the $_REQUEST['_method'] parameter on any HTTP verb (including safe verbs such as GET), with no opt-in and no whitelist of permitted target methods. A GET request can silently become a DELETE or PUT, enabling CSRF escalation against destructive endpoints, bypass of middleware gated on unsafe verbs, and cache poisoning between CDN and origin. This vulnerability is fixed in 3.18.1.
Frequently asked questions
- What is CVE-2026-42551?
- Flight is an extensible micro-framework for PHP. Prior to 3.18.1, Request::getMethod() unconditionally honors the X-HTTP-Method-Override header and the $_REQUEST['_method'] parameter on any HTTP verb (including safe verbs such as GET), with no opt-in and no whitelist of permitted target methods. A GET request can silently become a DELETE or PUT, enabling CSRF escalation against destructive endpoints, bypass of middleware gated on unsafe verbs, and cache poisoning between CDN and origin. This vulnerability is fixed in 3.18.1.
- How severe is CVE-2026-42551?
- CVE-2026-42551 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity high, and availability none.
- Is CVE-2026-42551 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (23rd percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2026-42551?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2026-42551 have an EU (EUVD) identifier?
- Yes. CVE-2026-42551 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-30150.
- When was CVE-2026-42551 published?
- CVE-2026-42551 was published on 2026-05-13 and last updated on 2026-06-17.
References
Other CWE-436 vulnerabilities
- CVE-2023-24813 — Critical (CVSS 10.0): Dompdf is an HTML to PDF converter written in php. Due to the difference in the attribute parser of Dompdf and…
- CVE-2026-8034 — Critical (CVSS 9.8): A server-side request forgery (SSRF) vulnerability was identified in the GitHub Enterprise Server notebook viewer that…
- CVE-2021-45327 — Critical (CVSS 9.8): Gitea before 1.11.2 is affected by Trusting HTTP Permission Methods on the Server Side when referencing the vulnerable…
- CVE-2020-10180 — Critical (CVSS 9.8): The ESET AV parsing engine allows virus-detection bypass via a crafted BZ2 Checksum field in an archive. This affects…
- CVE-2019-19589 — Critical (CVSS 9.8): The Lever PDF Embedder plugin 4.4 for WordPress does not block the distribution of polyglot PDF documents that are…
- CVE-2026-14198 — Critical (CVSS 9.1): @fastify/middie versions 9.1.0 through 9.3.2 decode the encoded slash %2F inside path parameter values before matching…