Affected: brianmario yajl-ruby

yajl-ruby is a C binding to the YAJL JSON parsing and generation library. The 1.x branch and the 2.x branch of `yajl` contain an integer overflow which leads to subsequent heap memory corruption when dealing with large (~2GB) inputs. The reallocation logic at `yajl_buf.c#L64` may result in the `need` 32bit integer wrapping to 0 when `need` approaches a value of 0x80000000 (i.e. ~2GB of data), which results in a reallocation of buf->alloc into a small heap chunk. These integers are declared as `size_t` in the 2.x branch of `yajl`, which practically prevents the issue from triggering on 64bit platforms, however this does not preclude this issue triggering on 32bit builds on which `size_t` is a 32bit integer. Subsequent population of this under-allocated heap chunk is based on the original buffer size, leading to heap memory corruption. This vulnerability mostly impacts process availability. Maintainers believe exploitation for arbitrary code execution is unlikely. A patch is available and anticipated to be part of yajl-ruby version 1.4.2. As a workaround, avoid passing large inputs to YAJL.

Affected: RubyGems: yajl-ruby

_NOTE: A previous patch, 1.4.2, fixed the heap memory issue, but could still lead to a DoS infinite loop. Please update to version 1.4.3_

The 1.x branch and the 2.x branch of [yajl](https://github.com/lloyd/yajl) contain an integer overflow which leads to subsequent heap memory corruption when dealing with large (~2GB) inputs.

### Details

The [reallocation logic at yajl_buf.c#L64](https://github.com/brianmario/yajl-ruby/blob/7168bd79b888900aa94523301126f968a93eb3a6/ext/yajl/yajl_buf.c#L64) may result in the `need` 32bit integer wrapping to 0 when `need` approaches a value of 0x80000000 (i.e. ~2GB of data), which results in a reallocation of buf->alloc into a small heap chunk.

These integers are declared as `size_t` in the 2.x branch of `yajl`, which practically prevents the issue from triggering on 64bit platforms, however this does not preclude this issue triggering on 32bit builds on which `size_t` is a 32bit integer.

Subsequent population of this under-allocated heap chunk is based on the original buffer size, leading to heap memory corruption.

### Impact

We rate this as a moderate severity vulnerability which mostly impacts process availability as we believe exploitation for arbitrary code execution to be unlikely.

### Patches

Patched in yajl-ruby 1.4.3

### Workarounds

Avoid passing large inputs to YAJL

### References https://github.com/brianmario/yajl-ruby/blob/7168bd79b888900aa94523301126f968a93eb3a6/ext/yajl/yajl_buf.c#L64

### For more information If you…