{"schema":"threatline.record/2","record":{"id":"CVE-2026-54899","aliases":["GHSA-2cw7-v8ff-p88r"],"summary":"Oj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle","details":"### Summary\n\nDisabling `symbol_keys` on a reused `Oj::Parser` instance triggers a heap use-after-free. When `symbol_keys` is toggled from `true` to `false`, `opt_symbol_keys_set` frees the internal key cache (`cache_free`) but does not clear the pointer. The next `parse` call reads from the freed cache via `cache_intern`, producing a use-after-free.\n\n### Version\n\n- **Software**: oj gem\n- **Affected**: all versions with `ext/oj/usual.c`\n- **Latest tested**: 3.17.1 (confirmed present)\n\n### Details\n\n`ext/oj/usual.c`, `opt_symbol_keys_set`:\n\n```c\n// usual.c:1043–1051\nif (symbol_keys) {\n    d->key_cache = cache_create(...);   // allocate\n} else {\n    cache_free(d->key_cache);           // free — but d->key_cache pointer not NULLed\n}\n```\n\nOn the next parse call, `cache_key` → `cache_intern` reads from `d->key_cache` which now points to freed memory.\n\nASAN report:\n```\n==145265==ERROR: AddressSanitizer: heap-use-after-free on address 0x50b00001a318\nREAD of size 8 at 0x50b00001a318 thread T0\n    #0 cache_intern            /ext/oj/cache.c:328\n    #1 cache_key               /ext/oj/usual.c:161\n    #2 close_object            /ext/oj/usual.c:285\n    #3 parse                   /ext/oj/parser.c:693\n    #4 parser_parse            /ext/oj/parser.c:1408\nfreed by thread T0 here:\n    #0 free\n    #1 cache_free              /ext/oj/cache.c:277\n    #2 opt_symbol_keys_set     /ext/oj/usual.c:1051\n    #3 option                  /ext/oj/usual.c:1111\n    #4 parser_missing          /ext/oj/parser.c:1362\n0x50b00001a318 is 40 bytes inside freed 112-byte region [fd]fd fd fd fd fd fd fd\n```\n\n### Reproduce\n\n```ruby\nrequire 'oj'\np = Oj::Parser.new(:usual, symbol_keys: true)\np.symbol_keys = false     # frees cache without nulling pointer\np.parse('{\"attacker\":1}') # UAF: reads freed cache\n```","categories":["Libraries & packages"],"product":"oj","vendor":"ohler55","ecosystem":"rubygems","affected_ranges":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-2cw7-v8ff-p88r","source_modified_at":"2026-10-06T19:52:38Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"rubygems","name":"oj"},"range":"< 3.17.2"},{"source":"CVE List","source_url":"https://www.cve.org/CVERecord?id=CVE-2026-54899","source_modified_at":"2026-07-01T14:26:28.538Z","fetched_at":"2026-10-23T18:45:31.882637Z","product":"oj","vendor":"ohler55","versions":[{"version":"< 3.17.2","status":"affected"}],"defaultStatus":null},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-2cw7-v8ff-p88r","source_modified_at":"2026-10-06T20:00:05.191640486Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"RubyGems","name":"oj","purl":"pkg:gem/oj"},"ranges":[{"events":[{"introduced":"0"},{"fixed":"3.17.2"}],"type":"ECOSYSTEM"}],"versions":["0.5","0.5.1","0.5.2","0.6.0","0.7.0","0.8.0","0.9.0","1.0.0","1.0.1","1.0.2","1.0.3","1.0.4","1.0.5","1.0.6","1.1.0","1.1.1","1.2.0","1.2.1","1.2.10","1.2.11","1.2.12","1.2.13","1.2.2","1.2.3","1.2.4","1.2.5","1.2.6","1.2.7","1.2.8","1.2.9","1.3.0","1.3.2","1.3.4","1.3.5","1.3.6","1.3.7","1.4.0","1.4.1","1.4.2","1.4.3","1.4.4","1.4.5","1.4.6","1.4.6a2","1.4.7","2.0.0","2.0.1","2.0.10","2.0.11","2.0.12"]}],"fixed_versions":[{"source":"GitHub Advisory Database","source_url":"https://github.com/advisories/GHSA-2cw7-v8ff-p88r","source_modified_at":"2026-10-06T19:52:38Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"rubygems","name":"oj"},"version":"3.17.2"},{"source":"OSV","source_url":"https://osv.dev/vulnerability/GHSA-2cw7-v8ff-p88r","source_modified_at":"2026-10-06T20:00:05.191640486Z","fetched_at":"2026-10-23T18:42:43.628194Z","package":{"ecosystem":"RubyGems","name":"oj","purl":"pkg:gem/oj"},"version":"3.17.2"}],"cvss":8.7,"severity":"High","kev":{"listed":false},"epss":{"probability":0.00333,"percentile":0.25278,"score_date":"2026-10-23"},"published_at":"2026-06-30T23:03:15.696Z","modified_at":"2026-10-06T20:00:05.191640486Z","provenance":[{"source":"GitHub Advisory Database","url":"https://github.com/advisories/GHSA-2cw7-v8ff-p88r","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-06T19:52:38Z"},{"source":"CVE List","url":"https://www.cve.org/CVERecord?id=CVE-2026-54899","fetched_at":"2026-10-23T18:45:31.882637Z","source_modified_at":"2026-07-01T14:26:28.538Z"},{"source":"OSV","url":"https://osv.dev/vulnerability/GHSA-2cw7-v8ff-p88r","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-06T20:00:05.191640486Z"},{"source":"EPSS","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-54899","fetched_at":"2026-10-23T18:42:43.628194Z","source_modified_at":"2026-10-23"}],"sources":["GitHub Advisory Database","CVE List","OSV","EPSS"],"references":[{"source":"CVE List","url":"https://github.com/ohler55/oj/security/advisories/GHSA-2cw7-v8ff-p88r","tags":["exploit"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-54899","source":"GitHub Advisory Database"},{"url":"https://github.com/rubysec/ruby-advisory-db/blob/master/gems/oj/CVE-2026-54899.yml","source":"GitHub Advisory Database"},{"url":"https://www.cve.org/CVERecord/SearchResults?query=CVE-2026-54899","source":"GitHub Advisory Database"},{"url":"https://github.com/advisories/GHSA-2cw7-v8ff-p88r","source":"GitHub Advisory Database"}],"locations":[],"motoko_assessment":{"status":"requires_architecture_review","automatic_remediation":false},"cve_state":"PUBLISHED","ssvc":{"exploitation":"poc","automatable":"no","technical_impact":"partial","assessed_at":"2026-07-01T13:38:09.223016Z"},"classification":{"method":"product-first software-layer rules","rules_version":"2.1","matched_on":"ecosystem","confidence":"heuristic","reviewed":false},"change_timestamp":"2026-10-06T20:00:05.191640486Z","content_hash":"1fbdadbdc6cd6a924286cb45f67ede359ae178d2bb8e27d20dda441cde864c4c"}}