CVE-2020-12762: json-c · Out-of-bounds Write
Source CVE Database V5
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 15:59 UTC
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 9 May 2020
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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
| Product | Affected | Fixed in |
|---|---|---|
GitHubjson-c/json-cpkg:github/json-c/json-cOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
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
- github.com/json-c/json-c/pull/592 (opens in a new tab)
- github.com/rsyslog/libfastjson/issues/161 (opens in a new tab)
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CQQRRGBQCAWNCCJ2HN3W5SSCZ4QGMXQI/ (opens in a new tab)
- usn.ubuntu.com/4360-1/ (opens in a new tab)
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/CBR36IXYBHITAZFB5PFBJTED22WO5ONB/ (opens in a new tab)
- lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/W226TSCJBEOXDUFVKNWNH7ETG7AR6MCS/ (opens in a new tab)
- lists.debian.org/debian-lts-announce/2020/05/msg00032.html (opens in a new tab)
- lists.debian.org/debian-lts-announce/2020/05/msg00034.html (opens in a new tab)
- usn.ubuntu.com/4360-4/ (opens in a new tab)
- security.gentoo.org/glsa/202006-13 (opens in a new tab)
- lists.debian.org/debian-lts-announce/2020/07/msg00031.html (opens in a new tab)
- debian.org/security/2020/dsa-4741 (opens in a new tab)
- security.netapp.com/advisory/ntap-20210521-0001/ (opens in a new tab)
- cert-portal.siemens.com/productcert/pdf/ssa-637483.pdf (opens in a new tab)
- lists.debian.org/debian-lts-announce/2023/06/msg00023.html (opens in a new tab)