How severe is CVE-2018-6519?

CVE-2018-6519 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2018-6519?

CVE-2018-6519 affects the following packages: simplesamlphp/saml2 (Packagist), simplesamlphp/saml2 (Packagist), simplesamlphp/saml2 (Packagist). Ecosystems affected: Packagist.

How do I fix CVE-2018-6519?

Update simplesamlphp/saml2 to 1.10.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-6519 is resolved across your whole dependency graph.

How do I detect CVE-2018-6519 in my Packagist dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for simplesamlphp/saml2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2018-6519 if there is no patch (or I can't update yet)?

Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Is CVE-2018-6519 actively exploited in the wild?

No public exploit code has been indexed for CVE-2018-6519 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2018-6519?

CVE-2018-6519 has an EPSS (Exploit Prediction Scoring System) score of 1.7%, placing it in the 77th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2018-6519?

CVE-2018-6519 is classified as CWE-74 (CWE-74). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2018-6519 published, and has it been updated?

CVE-2018-6519 was published on February 2, 2018 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐘

🐘 Packagist

Not in CISA KEV

HIGH severity

CVE-2018-6519 — saml2

HIGH

CVE-2018-6519 is a high-severity (CVSS 7.5) CWE-74 vulnerability in simplesamlphp/saml2. A fix is available for simplesamlphp/saml2 — see the affected versions and patch details below.

SimpleSAMLphp SAML2 library Regular Expression Denial of Service vulnerability

Also known asGHSA-hhm8-2j4g-mpgg

Published

Feb 2, 2018

Updated

Oct 24, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Nov 6, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

1.7%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs77th percentile — riskier than 77% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected

🐘simplesamlphp/saml2🐘simplesamlphp/saml2🐘simplesamlphp/saml2

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Packagist packages — download data is not available via public APIs for these ecosystems.

Description

The SAML2 library before 1.10.4, 2.x before 2.3.5, and 3.x before 3.1.1 in SimpleSAMLphp has a Regular Expression Denial of Service vulnerability for fraction-of-seconds data in a timestamp.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐘Packagist	`simplesamlphp/saml2`	all versions	1.10.4`composer require simplesamlphp/saml2:^1.10.4`
🐘Packagist	`simplesamlphp/saml2`	≥ 2.0&&< 2.3.5	2.3.5`composer require simplesamlphp/saml2:^2.3.5`
🐘Packagist	`simplesamlphp/saml2`	≥ 3.0&&< 3.1.1	3.1.1`composer require simplesamlphp/saml2:^3.1.1`

Affected Products

2 products · 5 configurations

debian linuxdebian

2 versions

8.09.0

Application

saml2simplesamlphp

≥ 3.0.0 && < 3.1.1

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for simplesamlphp/saml2, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update simplesamlphp/saml2 to 1.10.4 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2018-6519 is resolved across your whole dependency graph.
Workarounds
Cap what an attacker can consume: apply request size, rate and timeout limits in front of the affected component, and run it with memory and CPU limits so exhaustion degrades one worker rather than the whole service.

Frequently Asked Questions

The SAML2 library before 1.10.4, 2.x before 2.3.5, and 3.x before 3.1.1 in SimpleSAMLphp has a Regular Expression Denial of Service vulnerability for fraction-of-seconds data in a timestamp.

O3 Security · Impact-Aware SCA

Is CVE-2018-6519 in your dependencies?

Find it across Packagist, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

7.5/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

High

Raw vector

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

CWE Classification

CWE-74CWE-74

Weaponization

No Nuclei template, Metasploit module or public proof-of-concept found.

OpenSSF Scorecard

Package health score

security-advisories

4.8/10

Maintained10/10

Code-Review10/10

Branch-Protection0/10

Assessed Nov 2, 2026

Timeline

Disclosed

Feb 2, 2018

Last updated

Oct 24, 2026

Identifiers

CVE-2018-6519

GHSA-hhm8-2j4g-mpgg

References

Advisorysimplesamlphp.org · 201801 01 Advisorydebian.org · dsa 4127 Advisorynvd.nist.gov · CVE 2018 6519 Webgithub.com · CVE 2018 6519.yaml Packagegithub.com · simplesamlphp

Related vulnerabilities

This CVE is high severity; 7 of 8 other CVEs affecting simplesamlphp/saml2 are rated as high or higher (top: critical).

CVE-2026-49289CVE-2026-49283CVE-2025-27773CVE-2024-52806CVE-2023-49087CVE-2018-7711CVE-2016-9814CVE-2018-7644

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026

CVE-2018-6519 — saml2

EPSS Exploitation Probability

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

Description

Affected Packages

Affected Products

Detection & mitigation playbook

Detect

Fix

Workarounds

Frequently Asked Questions

Is CVE-2018-6519 in your dependencies?