How severe is CVE-2026-15996?

CVE-2026-15996 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-15996 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-15996?

CVE-2026-15996 affects Github Enterprise Server. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-15996?

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-2026-15996 published?

CVE-2026-15996 was published on 2026-08-05 and last updated on 2026-08-18.

CVE-2026-15996

CVE-2026-15996 is a high-severity vulnerability in Github Enterprise Server with a CVSS 3.x base score of 7.5. 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-674.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v4: 6.6
EPSS exploit prediction: 0% (37th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-674
Affected product: Github Enterprise Server
Published: 2026-08-05
Last modified: 2026-08-18

Description

A denial of service vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to cause excessive CPU consumption and exhaust the pool of request-handling worker processes by sending a crafted form-encoded HTTP POST request containing deeply nested parameters. Because request parameters were parsed before routing and authentication, any POST endpoint could be used to trigger the condition, which could render the instance unresponsive. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.3, 3.19.7, 3.18.10, and 3.17.16.

Frequently asked questions

What is CVE-2026-15996?: A denial of service vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated attacker to cause excessive CPU consumption and exhaust the pool of request-handling worker processes by sending a crafted form-encoded HTTP POST request containing deeply nested parameters. Because request parameters were parsed before routing and authentication, any POST endpoint could be used to trigger the condition, which could render the instance unresponsive. This vulnerability affected all versions of GitHub Enterprise Server prior to 3.21 and was fixed in versions 3.20.3, 3.19.7, 3.18.10, and 3.17.16.
How severe is CVE-2026-15996?: CVE-2026-15996 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-15996 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (37th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-15996?: CVE-2026-15996 affects Github Enterprise Server. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-15996?: 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-2026-15996 published?: CVE-2026-15996 was published on 2026-08-05 and last updated on 2026-08-18.

References

Affected products (1)

cpe:2.3:a:github:enterprise_server:*:*:*:*:*:*:*:*

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