An issue was discovered in Mbed TLS versions from 2.19.0 up to 3.6.5, Mbed TLS 4.0.0.
Priority MEDIUM 49CWE-250Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Privilege escalation, Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- No fix listed
Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA. Impact type from CWE-250 and CWE-502.
Summary
An issue was discovered in Mbed TLS versions from 2.19.0 up to 3.6.5, Mbed TLS 4.0.0. Insufficient protection of serialized SSL context or session structures allows an attacker who can modify the serialized structures to induce memory corruption, leading to arbitrary code execution. This is caused by Incorrect Use of Privileged APIs.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00442 38th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| — | — | all versions | — | No fix listed | CNA |
- — Vendor— Affected all versions Fixed in — No fix listed CNA
Remediation
No fixed version listed by the sources yet.
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2026-34877
- 2026-10-03 Alias added: GHSA-xg3m-c464-j5fh
- 2026-10-25 EPSS moved to the below the 50th percentile
References
Sources
- CVE-2026-34877 · CVE Program
- CVE-2026-34877 · NVD
- FIRST EPSS
- GHSA-xg3m-c464-j5fh · GitHub Advisory Database · CC BY 4.0
- CVE-2026-34877 · Red Hat security data · CC BY 4.0
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