Memory corruption via printbuf integer overflow
Published May 9, 2020 · Updated Nov 3, 2025
Out-of-bounds write in json-c through 0.14 allows attackers to corrupt memory via a large JSON file supplied to the parser. The printbuf_memappend routine adds the current buffer position, input size, and terminator without preventing signed-integer overflow, so capacity checks can pass before bytes are written beyond the allocated buffer. Local users must cause an application to parse attacker-controlled oversized JSON; the result is a crash or memory corruption with potential integrity, confidentiality, and availability impact.
Summary
What happened
Out-of-bounds write in json-c through 0.14 allows attackers to corrupt memory via a large JSON file supplied to the parser. The printbuf_memappend routine adds the current buffer position, input size, and terminator without preventing signed-integer overflow, so capacity checks can pass before bytes are written beyond the allocated buffer. Local users must cause an application to parse attacker-controlled oversized JSON; the result is a crash or memory corruption with potential integrity, confidentiality, and availability impact.
The record
- CVE
- CVE-2020-12762
- Published
- May 9, 2020
- Updated
- Nov 3, 2025
- Vendor
- Unknown vendor
- Product
- Unknown product
- Classifications
- CWE-787, T1203
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- May 9, 2020CVE publishedPublication date reported by the CVE source.
- Nov 3, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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What is affected?
Affected products and versions are unavailable in this record.
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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.
Public exploit references
- json-c printbuf out-of-bounds write proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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