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UBUNTU-CVE-2021-42836
GJSON before 1.9.3 allows a ReDoS (regular expression denial of service) attack.
AI summary snake-internal / snake-template-v1
A weakness called UBUNTU-CVE-2021-42836 was discovered in GJSON before 1.9.3 allows a.
Severity is Info. Low severity or not yet rated.
What you should do: update the affected software to the latest version. If unsure, ask your IT team or search the vendor's site for "GJSON before 1.9.3 allows a UBUNTU-CVE-2021-42836".
UBUNTU-CVE-2021-42836 (GJSON before 1.9.3 allows a). Severity: Info.
Response plan:
1. Check the vendor advisory for affected versions and the patched release.
2. If a vulnerable version is running in production, schedule maintenance (urgency from KEV/CVSS).
3. If no patch yet, mitigate via WAF rule, disabling the affected feature, etc.
4. Monitor logs / SIEM for known IOC and PoC signatures of this CVE.
PoCs and fix commits: see the 'References' section, MITRE, and NVD.
❓ What is the problem
A weakness (UBUNTU-CVE-2021-42836) in GJSON before 1.9.3 allows a. A serious software flaw has been identified.
📍 Affected scope
Target versions of GJSON before 1.9.3 allows a (see vendor advisory). If running in production, identify exposure immediately.
🔥 Severity
Severity: Info. Low severity or not yet rated.
🔧 How to fix
Update to the patched release as listed in the vendor advisory.
🛡️ Workaround
If a patch is not yet available, consider disabling the affected feature, applying WAF rules, blocking via network ACLs, or isolating the vulnerable version.
🔍 Detection
Check version information, scan dependencies via SBOM, and monitor SIEM for IOC and PoC signatures related to this CVE.
Affected packages
Ubuntu:20.04:LTS
golang-github-tidwall-gjson
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:22.04:LTS
golang-github-tidwall-gjson
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:24.04:LTS
golang-github-tidwall-gjson
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:25.10
golang-github-tidwall-gjson
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
Ubuntu:26.04:LTS
golang-github-tidwall-gjson
[{"type":"ECOSYSTEM","events":[{"introduced":"0"}]}]
References
- report https://ubuntu.com/security/CVE-2021-42836
- report https://github.com/tidwall/gjson/commit/590010fdac311cc8990ef5c97448d4fec8f29944
- report https://github.com/tidwall/gjson/commit/77a57fda87dca6d0d7d4627d512a630f89a91c96
- report https://github.com/tidwall/gjson/issues/236
- report https://github.com/tidwall/gjson/issues/237
- report https://github.com/tidwall/gjson/compare/v1.9.2...v1.9.3
- report https://www.cve.org/CVERecord?id=CVE-2021-42836