Vulnerability in Mbed TLS (CVE-2026-34871)
Summary
Vulnerability in Mbed TLS (CVE-2026-34871). Confidential information can be exposed externally.
Original description
The description as published by the source.
An issue was discovered in Mbed TLS before 3.6.6 and 4.x before 4.1.0 and TF-PSA-Crypto before 1.1.0. There is a Predictable Seed in a Pseudo-Random Number Generator (PRNG).
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-34871 has been found in Mbed TLS.
Confidential information can be exposed externally. CVSS score: 6.7/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Mbed TLS CVE-2026-34871" on the vendor's site.
CVE-2026-34871 (Mbed TLS) — CWE-338 / CVSS v3 6.7
Attack vector: local / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-338) exists in Mbed TLS.
Check the vendor advisory for the affected versions of Mbed TLS.
Severity: Medium (CVSS 6.7/10). Confidential information can be exposed externally.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
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1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Mbed TLS を使っているサービスとバージョンを洗い出す。
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2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-34871 mbedtls Fixed in: 2.16.9-0.1+deb11u4
- Ubuntu UBUNTU-CVE-2026-34871 mbedtls
References
- patch cve@mitre.org
- patch cve@mitre.org