CVE catalog
CVE-2026-71847
Ruby JSON is a JSON implementation for Ruby. From 2.20.0 until 2.21.2, Ruby's JSON native C extension clears the consumed JSON::ResumableParser input buffer but leaves state.start, state.cursor, and s
- Severity
- High · CVSS 8.7
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.43% · Oct 25, 2026
Ruby JSON is a JSON implementation for Ruby. From 2.20.0 until 2.21.2, Ruby's JSON native C extension clears the consumed JSON::ResumableParser input buffer but leaves state.start, state.cursor, and state.end pointing into released storage. When partial_value reconstructs an incomplete object containing duplicate keys, the duplicate-key warning path calls cursor_position, which dereferences those stale pointers. This results in a heap-use-after-free and can terminate the Ruby process. An attacker who can supply JSON stream data to an application using JSON::ResumableParser may cause process termination when the application calls partial_value on incomplete attacker-controlled input containing duplicate object keys. This issue has been fixed in version 2.21.2.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | ruby-json | sid | 3.1.0+dfsg-1 | not affected |
| Debian | ruby-json | forky | 3.1.0+dfsg-1 | not affected |
| Debian | ruby-json | trixie | 2.9.1+dfsg-1 | not affected |
| Debian | ruby-json | bookworm | 2.6.3+dfsg-1 | not affected |
| Rubygems | json | Not reported | 2.21.2 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | ruby-json | source | sid | Not affected | unimportant | Not reported | Not reported |
| Debian | ruby-json | source | forky | Not affected | unimportant | Not reported | Not reported |
| Debian | ruby-json | source | trixie | Not affected | unimportant | Not reported | Not reported |
| Debian | ruby-json | source | bookworm | Not affected | unimportant | Not reported | Not reported |
| Rubygems | json | rubygems | Not reported | 2.21.2 | Not reported | Not reported | Not reported |
OpenFactory catalog packages
[Debian 13 (Trixie)]
[Debian 12 (Bookworm)]
- [ruby-json]Not affected
Details (2)
2.6.3+dfsg-1· amd64 · bookwormNot affected
nvd · ruby-json · debian · bookworm
2.6.3+dfsg-1· arm64 · bookwormNot affected
nvd · ruby-json · debian · bookworm
Observed:
References
- [https://ftp.suse.com/pub/projects/security/csaf/opensuse-su-2026_22068-1.json]
- [https://github.com/advisories/GHSA-9hj4-r449-hfvc]
- [https://github.com/ruby/json/security/advisories/GHSA-9hj4-r449-hfvc]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-71847]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-71847]
- [https://security-tracker.debian.org/tracker/CVE-2026-71847]
- [https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-71847.json]
[Debian Security Tracker] · [FIRST EPSS] · [GitHub Advisory Database] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database] · [Red Hat security advisories and VEX] · [SUSE security advisories and VEX]