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CVE-2026-39979 is an out-of-bounds read vulnerability in jq's libjq library affecting the jv_parse_sized() API. The API is designed to accept a counted input buffer together with an explicit length, but in the error-handling path for malformed JSON it formats the original input using a string conversion that expects a NUL-terminated buffer rather than honoring the supplied length. As a result, when a caller passes malformed JSON in a non-NUL-terminated buffer, the error construction logic can read past the end of the provided buffer while searching for a terminator. The flaw is reachable by applications embedding libjq and invoking jv_parse_sized() on untrusted data. Depending on surrounding memory layout and runtime conditions, the resulting out-of-bounds read can disclose adjacent memory contents or crash the process.
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Cross-references every affected SKU, including bundled OEM variants.
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