PatchTheCVECVE-2026-15996: A denial of service vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated a
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This month
HIGH 7.5REMOTEUPGRADE
CVE-2026-15996 is a high-severity flaw (CVSS 7.5) affecting enterprise server. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
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
Why this priority
- High severity
- Remotely exploitable, no login, no user action
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.5 (High) |
| Attack vector | Network (remote) |
| Attack complexity | Low |
| Privileges needed | None |
| User interaction | None |
| EPSS exploit chance | 0.8% (top 45%) |
| CISA exploited list | No |
| Weakness | CWE-674 |
| Published | 2026-08-05 |
| Last modified | 2026-10-23 |
Publisher (CNA): GitHub, Inc. (Products Only) · Vendor: github
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
github enterprise server UPGRADE
Affected: < 3.17.16 · >= 3.18.0 and < 3.18.10 · >= 3.19.0 and < 3.19.7 · >= 3.20.0 and < 3.20.3
Fixed in: 3.17.16, 3.18.10, 3.19.7, 3.20.3
Safe to downgrade to: a release before 3.18.0
1. Check installed version
apt-cache policy enterprise-server || rpm -q enterprise-server || enterprise-server --version
2. UPGRADE to 3.17.16 (Debian / Ubuntu)
sudo apt update && sudo apt install --only-upgrade enterprise-server
2. UPGRADE (RHEL / Amazon Linux / Fedora)
sudo dnf upgrade enterprise-server
Note
Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.
3. If no update is available yet, DOWNGRADE to a release before 3.18.0 (Debian / Ubuntu)
apt-cache madison enterprise-server
sudo apt install enterprise-server=<VERSION_BEFORE_3.18.0>
sudo apt-mark hold enterprise-server
3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)
dnf --showduplicates list enterprise-server
sudo dnf downgrade enterprise-server-<VERSION_BEFORE_3.18.0>
sudo dnf versionlock add enterprise-server
Downgrade risk
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
Exact fixes by distribution
Fedora 46 · kwin-zones · FIXED · 1.0.13-1.fc46 · FEDORA-2026-95888f332b · source
sudo dnf upgrade --advisory=FEDORA-2026-95888f332b
Fedora ELN · nginx-mod-brotli · FIXED · 1.0.0~rc-16.eln159 · FEDORA-2026-501a6a8273 · source
sudo dnf upgrade --advisory=FEDORA-2026-501a6a8273
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.
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Related CVEs
- CVE-2026-17556 CRITICAL 9.1 UPGRADE A path traversal vulnerability was identified in GitHub Enterprise Server that allowed an unauthenticated atta