CVE-2018-7711

HTTPRedirect.php in the saml2 library in SimpleSAMLphp before 1.15.4 has an incorrect check of return values in the signature validation utilities, allowing an attacker to get invalid signatures accepted as valid by forcing an error during validation. This occurs because of a dependency on PHP functionality that interprets a -1 error code as a true boolean value.

Published: 2018-03-05 Last update: 2026-06-16 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2018-7711 is rated Moderate Risk (55.9/100): CVSS High severity, with medium exploitation likelihood (EPSS 1.22%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2018-7711

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.32% 1.22% +0.90%
2 2026-01-14 0.21% 0.32% +0.11%
3 2025-11-21 — 0.21% —

Full EPSS history (14 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2018-7711

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
8.1 3.0 HIGH
CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:H)
Even with access, the exploit needs extra luck, timing, or a fussy environment to actually work.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 2.2 5.9 [email protected]
6.8 2.0 MEDIUM
AV:N/AC:M/Au:N/C:P/I:P/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 6.4 [email protected]

Weakness enumeration for CVE-2018-7711

GitHub Security Advisory for CVE-2018-7711

GHSA-g888-g2pp-82hf · Severity: high · Ecosystem: composer — SimpleSAMLphp saml2 incorrect signature validation

OS Trackers for CVE-2018-7711

vendor priority summary link
debian not yet assigned CVE-2018-7711 not yet assigned priority: Debian including 1 source packages (simplesamlphp), 4 status rows across 4 suites (bookworm, bullseye, forky, sid): resolved 4. https://security-tracker.debian.org/tracker/CVE-2018-7711
ubuntu medium CVE-2018-7711 medium priority: Ubuntu including 1 source packages (simplesamlphp), 20 status rows across 20 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, questing, trusty, upstream, xenial): not-affected 14, ignored 2, needed 2, DNE 1, released 1. https://ubuntu.com/security/CVE-2018-7711

Affected software / configurations for CVE-2018-7711

Vendor Product Version Raw CPE
simplesamlphp simplesamlphp < 1.15.4 cpe:2.3:a:simplesamlphp:simplesamlphp:*:*:*:*:*:*:*:*
simplesamlphp saml2 >= 1.0.0, < 1.10.6 cpe:2.3:a:simplesamlphp:saml2:*:*:*:*:*:*:*:*
simplesamlphp saml2 >= 2.0.0, < 2.3.8 cpe:2.3:a:simplesamlphp:saml2:*:*:*:*:*:*:*:*
simplesamlphp saml2 >= 3.0.0, < 3.1.4 cpe:2.3:a:simplesamlphp:saml2:*:*:*:*:*:*:*:*
debian debian_linux 7.0 cpe:2.3:o:debian:debian_linux:7.0:*:*:*:*:*:*:*

References for CVE-2018-7711

cvelogic Threat Intelligence