Vulnerabilities in pkg:gem/oj

{
  "schema_version" : "1.4.0",
  "id" : "GHSA-2cw7-v8ff-p88r",
  "modified" : "2026-10-06T19:52:36Z",
  "published" : "2026-06-19T19:34:30Z",
  "aliases" : [ "CVE-2026-54899" ],
  "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```",
  "severity" : [ {
    "type" : "CVSS_V4",
    "score" : "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"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "RubyGems",
      "name" : "oj"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "3.17.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/ohler55/oj/security/advisories/GHSA-2cw7-v8ff-p88r"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-54899"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ohler55/oj"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/rubysec/ruby-advisory-db/blob/master/gems/oj/CVE-2026-54899.yml"
  }, {
    "type" : "WEB",
    "url" : "https://www.cve.org/CVERecord/SearchResults?query=CVE-2026-54899"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-416" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-06-19T19:34:30Z",
    "nvd_published_at" : "2026-07-01T00:16:33Z"
  }
}