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VulnerabilityPublished Updated

CVE-2020-12762: json-c · Out-of-bounds Write

Source CVE Database V5

0

Not known to be exploited · CVSS 7.8 High.

Data as of 26 Oct 2026, 15:59 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
1.8% chance of exploitation in 30 days – higher than 79% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 9 May 2020

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Affected software

ProductAffectedFixed in
GitHubjson-c/json-cpkg:github/json-c/json-cOther threatsAffected
  • <=0.14
Fixed in–

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AI-suggested

To mitigate this vulnerability, European organizations should first identify all software and devices that incorporate json-c library versions up to 0.14. This can be done through software inventory and dependency analysis tools. If immediate patching is not feasible, organizations should restrict local access to systems running vulnerable software, enforce strict user privilege management, and monitor for unusual application crashes or memory corruption symptoms. Additionally, implementing application whitelisting and sandboxing can limit the impact of exploitation. For developers, validating and limiting the size of JSON inputs before processing can reduce the risk of triggering the integer overflow. Network segmentation and endpoint protection solutions should be employed to detect and prevent exploitation attempts. Finally, raising user awareness about the risks of processing untrusted JSON files locally can help reduce the chance of successful exploitation requiring user interaction.

Description

json-c through 0.14 has an integer overflow and out-of-bounds write via a large JSON file, as demonstrated by printbuf_memappend.

References

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