### Summary Disabling `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. ### Version - **Software**: oj gem - **Affected**: all versions with `ext/oj/usual.c` - **Latest tested**: 3.17.1 (confirmed present) ### Details `ext/oj/usual.c`, `opt_symbol_keys_set`: ```c // usual.c:1043–1051 if (symbol_keys) { d->key_cache = cache_create(...); // allocate } else { cache_free(d->key_cache); // free — but d->key_cache pointer not NULLed } ``` On the next parse call, `cache_key` → `cache_intern` reads from `d->key_cache` which now points to freed memory. ASAN report: ``` ==145265==ERROR: AddressSanitizer: heap-use-after-free on address 0x50b00001a318 READ of size 8 at 0x50b00001a318 thread T0 #0 cache_intern /ext/oj/cache.c:328 #1 cache_key /ext/oj/usual.c:161 #2 close_object /ext/oj/usual.c:285 #3 parse /ext/oj/parser.c:693 #4 parser_parse /ext/oj/parser.c:1408 freed by thread T0 here: #0 free #1 cache_free /ext/oj/cache.c:277 #2 opt_symbol_keys_set /ext/oj/usual.c:1051 #3 option /ext/oj/usual.c:1111 #4 parser_missing /ext/oj/parser.c:1362 0x50b00001a318 is 40 bytes inside freed 112-byte region [fd]fd fd fd fd fd fd fd ``` ### Reproduce ```ruby require 'oj' p = Oj::Parser.new(:usual, symbol_keys: true) p.symbol_keys = false # frees cache without nulling pointer p.parse('{"attacker":1}') # UAF: reads freed cache ```
### Summary Disabling `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. ### Version - **Software**: oj gem - **Affected**: all versions with `ext/oj/usual.c` - **Latest tested**: 3.17.1 (confirmed present) ### Details `ext/oj/usual.c`, `opt_symbol_keys_set`: ```c // usual.c:1043–1051 if (symbol_keys) { d->key_cache = cache_create(...); // allocate } else { cache_free(d->key_cache); // free — but d->key_cache pointer not NULLed } ``` On the next parse call, `cache_key` → `cache_intern` reads from `d->key_cache` which now points to freed memory. ASAN report: ``` ==145265==ERROR: AddressSanitizer: heap-use-after-free on address 0x50b00001a318 READ of size 8 at 0x50b00001a318 thread T0 #0 cache_intern /ext/oj/cache.c:328 #1 cache_key /ext/oj/usual.c:161 #2 close_object /ext/oj/usual.c:285 #3 parse /ext/oj/parser.c:693 #4 parser_parse /ext/oj/parser.c:1408 freed by thread T0 here: #0 free #1 cache_free /ext/oj/cache.c:277 #2 opt_symbol_keys_set /ext/oj/usual.c:1051 #3 option /ext/oj/usual.c:1111 #4 parser_missing /ext/oj/parser.c:1362 0x50b00001a318 is 40 bytes inside freed 112-byte region [fd]fd fd fd fd fd fd fd ``` ### Reproduce ```ruby require 'oj' p = Oj::Parser.new(:usual, symbol_keys: true) p.symbol_keys = false # frees cache without nulling pointer p.parse('{"attacker":1}') # UAF: reads freed cache ```
Update oj to 3.17.3 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanOj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle affects oj (rubygems). Severity is high. ### Summary Disabling `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. ### Version - **Software**: oj gem - **Affected**: all versions with `ext/oj/usual.c` - **Latest tested**: 3.17.1 (confirmed present) ### Details `ext/oj/usual.c`, `opt_symbol_keys_set`: ```c // usual.c:1043–1051 if (symbol_keys) { d->key_cache = cache_create(...); // allocate } else { cache_free(d->key_cache); // free — but d->key_cache pointer not NULLed } ``` On the next parse call, `cache_key` → `cache_intern` reads from `d->key_cache` which now points to freed memory. ASAN report: ``` ==145265==ERROR: AddressSanitizer: heap-use-after-free on address 0x50b00001a318 READ of size 8 at 0x50b00001a318 thread T0 #0 cache_intern /ext/oj/cache.c:328 #1 cache_key /ext/oj/usual.c:161 #2 close_object /ext/oj/usual.c:285 #3 parse /ext/oj/parser.c:693 #4 parser_parse /ext/oj/parser.c:1408 freed by thread T0 here: #0 free #1 cache_free /ext/oj/cache.c:277 #2 opt_symbol_keys_set /ext/oj/usual.c:1051 #3 option /ext/oj/usual.c:1111 #4 parser_missing /ext/oj/parser.c:1362 0x50b00001a318 is 40 bytes inside freed 112-byte region [fd]fd fd fd fd fd fd fd ``` ### Reproduce ```ruby require 'oj' p = Oj::Parser.new(:usual, symbol_keys: true) p.symbol_keys = false # frees cache without nulling pointer p.parse('{"attacker":1}') # UAF: reads freed cache ```
AI coding agents often install or upgrade packages automatically in rubygems. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| ojrubygems | <3.17.2 | 3.17.3 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL GuardUpdate oj to 3.17.3 if you use the affected versions. Test the change in a non-production environment first.
Local check
hol-guard supply-chain scanOj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle affects oj (rubygems). Severity is high. ### Summary Disabling `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. ### Version - **Software**: oj gem - **Affected**: all versions with `ext/oj/usual.c` - **Latest tested**: 3.17.1 (confirmed present) ### Details `ext/oj/usual.c`, `opt_symbol_keys_set`: ```c // usual.c:1043–1051 if (symbol_keys) { d->key_cache = cache_create(...); // allocate } else { cache_free(d->key_cache); // free — but d->key_cache pointer not NULLed } ``` On the next parse call, `cache_key` → `cache_intern` reads from `d->key_cache` which now points to freed memory. ASAN report: ``` ==145265==ERROR: AddressSanitizer: heap-use-after-free on address 0x50b00001a318 READ of size 8 at 0x50b00001a318 thread T0 #0 cache_intern /ext/oj/cache.c:328 #1 cache_key /ext/oj/usual.c:161 #2 close_object /ext/oj/usual.c:285 #3 parse /ext/oj/parser.c:693 #4 parser_parse /ext/oj/parser.c:1408 freed by thread T0 here: #0 free #1 cache_free /ext/oj/cache.c:277 #2 opt_symbol_keys_set /ext/oj/usual.c:1051 #3 option /ext/oj/usual.c:1111 #4 parser_missing /ext/oj/parser.c:1362 0x50b00001a318 is 40 bytes inside freed 112-byte region [fd]fd fd fd fd fd fd fd ``` ### Reproduce ```ruby require 'oj' p = Oj::Parser.new(:usual, symbol_keys: true) p.symbol_keys = false # frees cache without nulling pointer p.parse('{"attacker":1}') # UAF: reads freed cache ```
AI coding agents often install or upgrade packages automatically in rubygems. A high vulnerability in a dependency can be pulled into a project through a normal install or update without a human reviewing the change, expanding the blast radius from a single package to every agent workspace that depends on it.
| Package | Affected range | Fixed version |
|---|---|---|
| ojrubygems | <3.17.2 | 3.17.3 |
Fixed versions are reported by the source feed; confirm compatibility before updating.
Reported by GitHub Security Advisories (ghsa).
HOL Guard can help your team review package activity against supported protection paths.
Explore HOL Guard