undici vulnerable to TLS certificate validation bypass via dropped tls options in Agent
CVSS score
7.4
EPSS probability
%0.2
Risk score
0.0
Published
4 d ago
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Vulnerability description
CVE AI research
DayBreach AI Explanation
Verified against sourcesSources read
2
Source agreement
Tam uyum
Evidence confidence
%63
Short explanation
In the undici library, the Agent dispatcher passes constructor options through a JSON-based deep clone, causing custom checkServerIdentity callbacks to be dropped and leading to a TLS certificate validation bypass.
Applications relying on custom verification callbacks for certificate or public-key pinning become vulnerable to malicious server certificates being silently accepted, leading to confidentiality and integrity breaches.
What should be done?
- Upgrade undici to versions 6.29.1, 7.30.1, 8.12.2 or later
- Pass TLS options through connect instead of tls as a workaround
- Use requestTls and proxyTls for proxied destinations
Chain of evidence and sources
undici kütüphanesinin Agent dağıtıcısı, yapılandırma seçeneklerini JSON tabanlı derin kopyalamadan geçirdiği için tls seçeneğindeki işlevler düşer.
Özel checkServerIdentity geri çağırma işlevinin kaybolması sonucunda, düğümün varsayılan kontrollerini geçen geçersiz sertifikalar sessizce kabul edilir.
Bu açık, undici 6.29.1, 7.30.1 ve 8.12.2 sürümleriyle giderilmiştir.
Show the technical text from the sources
undici is an HTTP client library for Node.js. In versions 4.0.0 through 6.29.0, 7.0.0 through 7.30.0, and 8.0.0 through 8.12.1, its Agent dispatcher passes its constructor options through a JSON-based deep clone before forwarding them to each per-origin pool, and because JSON cannot represent functions, a caller-supplied tls option containing a checkServerIdentity callback is silently dropped before it reaches the TLS layer. As a result, a TLS peer whose certificate a custom checkServerIdentity was written to reject, but which passes Node's default hostname and chain checks, is silently accepted. Because Agent is the default dispatcher behind request, fetch, and setGlobalDispatcher, this affects the path most applications use, and EnvHttpProxyAgent is affected on its direct and no-proxy routes as well, while only applications that pass a function-valued tls option such as a custom checkServerIdentity for certificate or public-key pinning are at risk. The issue is fixed in undici 6.29.1, 7.30.1, and 8.12.2, which preserve the tls option outside the JSON clone so custom verification callbacks are forwarded unchanged, and users should upgrade to one of those versions or later. As a workaround, pass the TLS options through connect instead of tls, or for proxied destinations use requestTls and proxyTls.
CVSS vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
CWE: CWE-295
Explanation produced with the local gemini-flash-lite-latest model. Numerical metrics and the KEV, patch and exploit statuses are not determined by AI.
IMPACT: Affected Products and Software
Affected Products
The following products are affected by CVE-2026-109383 vulnerability. Where our threat engine knows the exact affected versions, they are listed below.
RED HAT CSAF/VEX: Product Impact Check
SCORING: CVSS from Multiple Sources
CVSS Scores
The Common Vulnerability Scoring System is a standardised framework for assessing the severity of vulnerabilities in software and systems. We collect and display CVSS scores from several sources for each CVE.
| SCORE | VERSION | SEVERITY | VECTOR | SOURCE |
|---|---|---|---|---|
| 9.1 | CVSS V31 | CRITICAL | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N | NVD |
| 7.4 | CVSS V3_1 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N | CVE CNA |
| 7.4 | CVSS V31 | HIGH | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N | NVD |
Patch and Remediation Guide
Solution & Remediation Advisory
1 düzeltme kanıtı bulundu; en az 3 ürün veya sürüm hâlâ etkileniyor ya da inceleniyor.
8.12.2+dfsg+~cs3.2.3-1Debian sid: 8.12.2+dfsg+~cs3.2.3-1
Public exploit and active exploitation status
Verified exploit intelligence
No verified public PoC, exploit repository or Metasploit module has been found for this CVE yet.
Weakness Classification and Attack Patterns (CWE & CAPEC)
CWE - Common Weakness Enumeration
While CVE identifies specific instances of vulnerabilities, CWE categorises the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-109383 is associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-109383 weaknesses.
Attack Vector and Accessibility
Official Sources and Advisories
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