Code execution via unprotected serialized TLS state
Published Apr 2, 2026 · Updated Apr 2, 2026
Unsafe deserialization in Mbed TLS 2.19.0 through 3.6.5 and 4.0.0 allows context-dependent attackers to execute arbitrary code. The session and context restoration APIs deserialize attacker-modified buffers as trusted internal state, allowing inconsistent fields to trigger out-of-bounds reads or writes. Exploitation requires an application to use TLS serialization and expose stored state without integrity protection; outcomes range from a process crash to application compromise.
Summary
What happened
Unsafe deserialization in Mbed TLS 2.19.0 through 3.6.5 and 4.0.0 allows context-dependent attackers to execute arbitrary code. The session and context restoration APIs deserialize attacker-modified buffers as trusted internal state, allowing inconsistent fields to trigger out-of-bounds reads or writes. Exploitation requires an application to use TLS serialization and expose stored state without integrity protection; outcomes range from a process crash to application compromise.
The record
- CVE
- CVE-2026-34877
- Published
- Apr 2, 2026
- Updated
- Apr 2, 2026
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-502, CWE-250
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Apr 2, 2026CVE publishedPublication date reported by the CVE source.
- Apr 2, 2026Record updatedLatest update available in the CVE record.
Exploitability
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What is affected?
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Published CVSS scores
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Attacks
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Public exploit references
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Technologies
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