phpseclib: X.509 certificate validation sends attacker-controlled outbound requests (server-side request forgery) via Authority Information Access

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Summary

CVECVE-2026-55599
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-22 21:16:25 UTC
Updated2026-06-22 21:16:25 UTC
Descriptionphpseclib is a PHP secure communications library. From 0.1.1 until 1.0.30, 2.0.55, and 3.0.54, when an application validates an untrusted X.509 certificate with phpseclib, X509::validateSignature() reads a URL out of that certificate's Authority Information Access (AIA) extension and connects to it. Attacker who supplies certificate fully controls host, port, and path of that connection. URL fetching is enabled by default, and no destination is blocked. An unauthenticated attacker can therefore make a validating server open connections to internal hosts and ports it should never reach, for example loopback 127.0.0.1, cloud metadata address 169.254.169.254, and internal-only services. This is a server-side request forgery (SSRF) caused by an insecure default. This vulnerability is fixed in 1.0.30, 2.0.55, and 3.0.54.

Risk And Classification

Primary CVSS: v3.1 5.8 MEDIUM from [email protected]

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

Problem Types: CWE-918 | CWE-918 CWE-918: Server-Side Request Forgery (SSRF)

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary5.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N
3.1CNADECLARED5.8MEDIUMCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Changed
Confidentiality
Low
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Phpseclib Phpseclib affected >= 0.1.1, < 1.0.30 Not specified
CNA Phpseclib Phpseclib affected >= 2.0.0, < 2.0.55 Not specified
CNA Phpseclib Phpseclib affected >= 3.0.0, < 3.0.54 Not specified

References

ReferenceSourceLinkTags
github.com/phpseclib/phpseclib/security/advisories/GHSA-m557-wrgg-6rp4 [email protected] github.com
CVE Program record CVE.ORG www.cve.org canonical
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