Crash via punycode decoder off-by-one
Published Nov 1, 2022 · Updated Apr 14, 2026
Stack buffer overflow in OpenSSL 3.0.0 through 3.0.6 allows remote attackers to crash TLS clients or servers via a crafted certificate. The ossl_punycode_decode function uses a greater-than bounds check, permitting written_out to equal max_out before memmove writes a four-byte unsigned integer past the stack buffer. Exploitation requires a CA-signed malicious certificate or continued verification after path-building failure; servers are exposed only when requesting client certificates, and code execution depends on platform mitigations and stack layout.
Summary
What happened
Stack buffer overflow in OpenSSL 3.0.0 through 3.0.6 allows remote attackers to crash TLS clients or servers via a crafted certificate. The ossl_punycode_decode function uses a greater-than bounds check, permitting written_out to equal max_out before memmove writes a four-byte unsigned integer past the stack buffer. Exploitation requires a CA-signed malicious certificate or continued verification after path-building failure; servers are exposed only when requesting client certificates, and code execution depends on platform mitigations and stack layout.
The record
- CVE
- CVE-2022-3602
- Published
- Nov 1, 2022
- Updated
- Apr 14, 2026
- Vendor
- Siemens
- Product
- SIMATIC RTLS Locating Manager
- Classifications
- CWE-120, CWE-787, T1190
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Nov 1, 2022CVE publishedPublication date reported by the CVE source.
- Apr 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=V2.13.0.0 <V2.13.0.3
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
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Technologies
Your stack
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Your stack
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