Nginx: When multiple server blocks are configured to share the same IP address and port, an attacker can use session
Affects nginxSource GCVE Database
Not known to be exploited · CVSS 4.3 Medium · fixed in 1.18.0-0ubuntu1.7 : update nginx when convenient.
Data as of 5 Nov 2026, 23:23 UTC
- EPSS
- 2.7% chance of exploitation in 30 days – higher than 86% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 1.18.0-0ubuntu1.7, 1.18.0-6ubuntu14.6, 1.24.0-2ubuntu7.3
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:NExploitation evidence
Disclosed: evidence found.
CVE published 5 Feb 2025
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade the Ubuntu nginx to 1.18.0-0ubuntu1.7 (package) or 1.18.0-6ubuntu14.6 (package) or 1.24.0-2ubuntu7.3 (package).
Patches and advisories
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 24.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=nobleOther threats | Affected
| Fixed in
|
Ubuntu 22.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=jammyOther threats | Affected
| Fixed in
|
Ubuntu 20.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=focalOther threats | Affected
| Fixed in
|
Ubuntu Pro 18.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=esm-infra/bionicOther threats | Affected
| Fixed in– |
Ubuntu Pro 16.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=esm-infra-legacy/xenialOther threats | Affected
| Fixed in– |
Ubuntu Pro 14.04 LTSnginxpkg:deb/ubuntu/nginx?arch=source&distro=esm-infra-legacy/trustyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available and users should update nginx packages to the fixed versions provided by Ubuntu: 1.18.0-0ubuntu1.7 for 20.04 LTS, 1.18.0-6ubuntu14.6 for 22.04 LTS, and 1.24.0-2ubuntu7.3 for 24.10. Applying these updates will remediate the vulnerability. Standard system updates will apply the necessary patches.
Description
Nginx versions prior to certain patched releases contain a vulnerability where multiple server blocks sharing the same IP address and port can allow an attacker to bypass client certificate authentication via TLS session resumption. This issue arises when TLS Session Tickets or SSL session cache are used in the default server performing client certificate authentication. The vulnerability affects specific Ubuntu package versions of nginx and has been fixed in updated package releases.
References
- ubuntu.com/security/CVE-2025-23419 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2025-23419 (opens in a new tab)
- openwall.com/lists/oss-security/2025/02/05/8 (opens in a new tab)
- github.com/nginx/nginx/commit/13935cf9fdc3c8d8278c70716417d3b71c36140e (opens in a new tab)
- ubuntu.com/security/notices/USN-7285-1 (opens in a new tab)