CVE-2016-2049: examples/consumer/common.php in JanRain PHP OpenID library (aka php-openid) improperly checks the openid.realm

This month

HIGH 8.8MITIGATE

CVE-2016-2049 is a high-severity flaw (CVSS 8.8) affecting php-openid. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

examples/consumer/common.php in JanRain PHP OpenID library (aka php-openid) improperly checks the openid.realm parameter against the SERVER_NAME element in the SERVER superglobal array, which might allow remote attackers to hijack the authentication of arbitrary users via vectors involving a crafted HTTP Host header.

Why this priority

High severity

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	8.8 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	2.2% (top 18%)
CISA exploited list	No
Weakness	CWE-284
Published	2016-02-01
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: janrain

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2016-02-01 21:59 UTCPublished CVE record published
2026-06-17 00:43 UTCUpdated Record last modified

janrain php-openid MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy php-openid || rpm -q php-openid || php-openid --version

No fixed or unaffected release known

Apply the vendor mitigation from the advisory, disable the affected feature, or restrict network access.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2016-2049?

php-openid: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2016-2049 being exploited?

CVE-2016-2049 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2016-2049 affect?

CVE-2016-2049 affects php-openid. Severity is high (CVSS 8.8). examples/consumer/common.php in JanRain PHP OpenID library (aka php-openid) improperly checks the openid.realm parameter against the SERVER_NAME element in the SERVER superglobal array, which might allow remote attackers to hijack the authe

How urgent is CVE-2016-2049?

Priority 51/100. High severity

Software pages

PHP vulnerabilities

Related CVEs

CVE-2013-4701 HIGH 7.5 UPGRADE Auth/Yadis/XML.php in PHP OpenID Library 2.2.2 and earlier allows remote attackers to read arbitrary files, se

References

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