CVE-2026-15996
Denial of service vulnerability in GitHub Enterprise Server allowed unauthenticated service disruption via deeply nested request parameters
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.
INFO
Published Date :
Aug. 5, 2026, 9:16 p.m.
Last Modified :
Aug. 5, 2026, 9:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | 82327ea3-741d-41e4-88f8-2cf9e791e760 | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update GitHub Enterprise Server to version 3.20.3 or later.
- Apply patches for versions 3.19.7, 3.18.10, or 3.17.16.
- Ensure request parsing occurs after authentication checks.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-15996.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-15996 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-15996
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-15996 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-15996 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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New CVE Received by [email protected]
Aug. 05, 2026
Action Type Old Value New Value Added Affected [{'vendor': 'GitHub', 'product': 'Enterprise Server', 'versions': [{'status': 'affected', 'changes': [{'at': '3.17.16', 'status': 'unaffected'}], 'version': '3.17.0', 'versionType': 'semver', 'lessThanOrEqual': '3.17.15'}, {'status': 'affected', 'changes': [{'at': '3.18.10', 'status': 'unaffected'}], 'version': '3.18.0', 'versionType': 'semver', 'lessThanOrEqual': '3.18.9'}, {'status': 'affected', 'changes': [{'at': '3.19.7', 'status': 'unaffected'}], 'version': '3.19.0', 'versionType': 'semver', 'lessThanOrEqual': '3.19.6'}, {'status': 'affected', 'changes': [{'at': '3.20.3', 'status': 'unaffected'}], 'version': '3.20.0', 'versionType': 'semver', 'lessThanOrEqual': '3.20.2'}], 'defaultStatus': 'affected'}] Added 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. Added CVSS V4.0 AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-674 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.17.16 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.18.10 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.19.7 Added Reference https://docs.github.com/en/[email protected]/admin/release-notes#3.20.3