CVE-2026-15996 json
Denial of service vulnerability in GitHub Enterprise Server allowed unauthenticated service disruption via deeply nested request parameters
published 2026-08-05 3 mo ago modified 2026-10-23 16 d ago also EUVD-2026-53611
- cvss
- 7.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.8%
- EPSS 0.8% chance of exploitation in 30 days, percentile 55%
- public exploits
- 0
- none known
Summary
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.
Patch / fix
- GitHub Enterprise Server 3.17.16, 3.18.10, 3.19.7, 3.20.3
CISA SSVC
- Exploitation
- none
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 3 mo ago
Exploit prediction
0.77% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 6.6 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U |
| CNA | 4.0 | 6.6 | CVSS:4.0/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 |
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected products
- GitHub Enterprise Server
Classification
- Weakness
-
- CWE-674 Uncontrolled Recursion
References
-
docs.github.com
/en/enterprise-server@3.17/admin/release-notes#3.17.16
release-notes, product
-
docs.github.com
/en/enterprise-server@3.18/admin/release-notes#3.18.10
release-notes, product
-
docs.github.com
/en/enterprise-server@3.19/admin/release-notes#3.19.7
release-notes, product
-
docs.github.com
/en/enterprise-server@3.20/admin/release-notes#3.20.3
release-notes, product
Sources
- CVE List CVE-2026-15996
- NVD CVE-2026-15996
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.
CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.