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Node.js SNI hostname case-sensitivity mTLS authorization bypass

IdentifiersCVE-2026-48928CWE-178

CVE-2026-48928 is a medium-severity Node.js TLS vulnerability affecting the 22.x, 24.x, and 26.x release lines. In multi-context mutual TLS (mTLS) deployments, Node.js performs inconsistent case-sensitive hostname matching for SNI contexts. The issue is described as an inconsistency in hostname matching, specifically involving uppercase SNI context matching, which can cause the wrong trust policy or authorization context to be applied. In affected configurations, this can bypass intended trust-policy enforcement in multi-context mTLS setups.

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ANALYST BRIEF

Impact, mitigation & remediation

What it means. What to do now. Patch path, mitigations, and the assume-compromise checklist.

Impact

What an attacker gets, and what they’ve been doing with it.

Successful exploitation can cause an mTLS authorization or trust-policy bypass. In practice, an attacker may be able to present a hostname/SNI value with case variations that causes Node.js to select or evaluate an unintended TLS context, weakening or bypassing the expected client-certificate authorization boundary for that virtual host or context.

Mitigation

If you can’t patch tonight, do this now.

If immediate patching is not possible, reduce exposure by avoiding multi-context mTLS configurations that rely on SNI-based hostname/context selection for security decisions, especially where distinct trust policies are bound to different hostnames. Normalize and strictly validate hostnames/SNI values consistently before policy selection where possible, and place affected services behind a front end or proxy that enforces canonical hostname handling and mTLS policy independently. These are compensating controls only; patching is required for complete remediation.

Remediation

Patch, then assume compromise.

Upgrade Node.js to a fixed release. The provided content identifies fixed versions in the June 18, 2026 security release as v22.23.0, v24.17.0, and v26.3.1 for the supported release lines. Additional reporting in the content references later patched versions v22.23.1, v24.17.1, and v26.3.2; upgrading to the latest available patched release on the relevant supported branch is the safest remediation.
PUBLIC EXPLOITS

Exploits

No public exploits tracked yet. Mallory keeps watching.

VALID 0 / 0 TOTALView more in app

No public exploit code observed for this vulnerability.

ACTIVITY FEED

Recent activity

5 sources tracked across advisories, community write-ups, and news. New activity surfaces here as Mallory finds it.

5 SOURCESView more in app
What this page doesn’t show

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Exposure mapping

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Threat actor evidence

Every observed campaign linking this CVE to a named adversary.

Associated malware

Malware families riding this exploit, with evidence and IOCs.

Detection signatures

YARA, Sigma, Snort, and vendor rules, auto-deployed to your SIEM.

Vendor-by-vendor mapping

Cross-references every affected SKU, including bundled OEM variants.

Social activity2

Community discussion across Reddit, Mastodon, and other social sources.

EXTERNAL REFERENCES
MITRE CVE
cve.org · CVE-2026-48928
NVD
nvd.nist.gov/vuln/detail/CVE-2026-48928
MITRE CWE · CWE-178
cwe.mitre.org