How severe is CVE-2015-8623?

CVE-2015-8623 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2015-8623 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-8623?

CVE-2015-8623 primarily affects Mediawiki. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2015-8623?

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.

When was CVE-2015-8623 published?

CVE-2015-8623 was published on 2017-03-23 and last updated on 2026-06-17.

CVE-2015-8623

CVE-2015-8623 is a high-severity vulnerability in Mediawiki with a CVSS 3.x base score of 8.8. 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-352.

Key facts

Severity: High (CVSS 3.x base score 8.8)
CVSS v2: 6.8
EPSS exploit prediction: 1% (50th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-352
Affected product: Mediawiki
Published: 2017-03-23
Last modified: 2026-06-17

Description

The User::matchEditToken function in includes/User.php in MediaWiki before 1.23.12 and 1.24.x before 1.24.5 does not perform token comparison in constant time before returning, which allows remote attackers to guess the edit token and bypass CSRF protection via a timing attack, a different vulnerability than CVE-2015-8624.

Frequently asked questions

What is CVE-2015-8623?: The User::matchEditToken function in includes/User.php in MediaWiki before 1.23.12 and 1.24.x before 1.24.5 does not perform token comparison in constant time before returning, which allows remote attackers to guess the edit token and bypass CSRF protection via a timing attack, a different vulnerability than CVE-2015-8624.
How severe is CVE-2015-8623?: CVE-2015-8623 has a CVSS 3.x base score of 8.8, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2015-8623 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (50th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-8623?: CVE-2015-8623 primarily affects Mediawiki. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-8623?: 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.
When was CVE-2015-8623 published?: CVE-2015-8623 was published on 2017-03-23 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:a:mediawiki:mediawiki:*:*:*:*:*:*:*:*
cpe:2.3:a:mediawiki:mediawiki:1.24.0:*:*:*:*:*:*:*
cpe:2.3:a:mediawiki:mediawiki:1.24.1:*:*:*:*:*:*:*
cpe:2.3:a:mediawiki:mediawiki:1.24.2:*:*:*:*:*:*:*
cpe:2.3:a:mediawiki:mediawiki:1.24.3:*:*:*:*:*:*:*
cpe:2.3:a:mediawiki:mediawiki:1.24.4:*:*:*:*:*:*:*

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