Nodejs: QUIC Server May Trigger Double Free When Processing INITIAL Packet (CVE-2026-18798)
Description
A vulnerability in the Node.js QUIC server component could cause a double free condition when processing INITIAL packets, potentially leading to a denial of service. This issue affects specific Ubuntu package versions of Node.js and OpenSSL. The vulnerability has a CVSS score of 7.5, indicating a medium severity level. A patch is available from Ubuntu to address this issue.
CVSS v3.1
Score 7.5high
Affected software
pkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps/xenialpkg:deb/ubuntu/nodejs?arch=source&distro=esm-apps/bionicpkg:deb/ubuntu/openssl-fips?arch=source&distro=fips-preview/jammypkg:deb/ubuntu/openssl-fips?arch=source&distro=fips-updates/jammypkg:deb/ubuntu/openssl-fips?arch=source&distro=fips-updates/noblepkg:deb/ubuntu/edk2?arch=source&distro=resolutepkg:deb/ubuntu/openssl?arch=source&distro=resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-18798 is a vulnerability in the Node.js QUIC server implementation where improper handling of INITIAL packets can trigger a double free condition. This flaw can cause the OpenSSL library, used by Node.js, to crash, resulting in a denial of service. The issue specifically affects certain Ubuntu package versions of Node.js and OpenSSL, primarily on Ubuntu 26.04 LTS and related Ubuntu Pro releases. The vulnerability has been assigned a CVSS v3.1 score of 7.5 (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H).
Potential Impact
A remote attacker can cause the OpenSSL library used by Node.js to crash by sending crafted QUIC INITIAL packets, leading to denial of service. There is no indication of confidentiality or integrity impact. No known exploits in the wild have been reported.
Mitigation Recommendations
An official patch is available and should be applied by updating to the fixed package versions provided by Ubuntu. After updating, a system reboot is recommended to ensure all changes take effect. The vendor advisory (Ubuntu Security Notice USN-8678-1) provides the necessary package versions for remediation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-18798
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:Pro:16.04:LTS","Ubuntu:Pro:18.04:LTS","Ubuntu:Pro:FIPS-preview:22.04:LTS","Ubuntu:Pro:FIPS-updates:22.04:LTS","Ubuntu:Pro:FIPS-updates:24.04:LTS","Ubuntu:26.04:LTS"]
- Cvss Version
- 3.1
Patch Information
Threat ID: 6a9053e9acd9273b496968b7
Added to database: 08/27/2026, 15:12:41 UTC
Last enriched: 09/10/2026, 07:53:43 UTC
Last updated: 10/10/2026, 18:48:17 UTC
Views: 74
Community Reviews
0 reviewsCrowdsource mitigation strategies, share intel context, and vote on the most helpful responses. Sign in to add your voice and help keep defenders ahead.
Want to contribute mitigation steps or threat intel context? Sign in or create an account to join the community discussion.
Actions
Updates to AI analysis require Pro Console access. Upgrade inside Console → Billing.
Need more coverage?
Upgrade to Pro Console for AI refresh and higher limits.
For incident response and remediation, OffSeq services can help resolve threats faster.
Latest Threats
Check if your credentials are on the dark web
Instant breach scanning across billions of leaked records. Free tier available.