jq is a command-line JSON processor. An integer overflow vulnerability exists through version 1.8.1 within the jvpstringappend() and jvpstringcopyreplacebad functions, where concatenating strings with a combined length exceeding 2^31 bytes causes a 32-bit unsigned integer overflow in the buffer allocation size calculation, resulting in a drastically undersized heap buffer. Subsequent memory copy operations then write the full string data into this undersized buffer, causing a heap buffer overflow classified as CWE-190 (Integer Overflow) leading to CWE-122 (Heap-based Buffer Overflow). Any system evaluating untrusted jq queries is affected, as an attacker can crash the process or potentially achieve further exploitation through heap corruption by crafting queries that produce extremely large strings. The root cause is the absence of string size bounds checking, unlike arrays and objects which already have size limits. The issue has been addressed in commit e47e56d226519635768e6aab2f38f0ab037c09e5.

jq is a command-line JSON processor. In 1.8.1 and earlier, the jq bytecode VM's data stack tracks its allocation size in a signed int. When the stack grows beyond ≈1 GiB (via deeply nested generator forks), the doubling arithmetic overflows. The wrapped value is passed to realloc and then used for a memmove with attacker-influenced offsets.

jq is a command-line JSON processor. In versions 1.8.1 and below, functions jvsetpath(), jvgetpath(), and delpathssorted() in jq's src/jvaux.c use unbounded recursion whose depth is controlled by the length of a caller-supplied path array, with no depth limit enforced. An attacker can supply a JSON document containing a flat array of ~65,000 integers (~200 KB) that, when used as a path argument by a trusted jq filter, exhausts the C call stack and crashes the process with a segmentation fault (SIGSEGV). This bypass works because the existing MAXPARSINGDEPTH (10,000) limit only protects the JSON parser, not runtime path operations where arrays can be programmatically constructed to arbitrary lengths. The impact is denial of service (unrecoverable crash) affecting any application or service that processes untrusted JSON input through jq's setpath, getpath, or delpaths builtins. This issue has been addressed in commit fb59f1491058d58bdc3e8dd28f1773d1ac690a1f.

jq is a command-line JSON processor. In 1.8.1 and earlier, unbounded recursion in jvobjectmergerecursive() allows a crafted jq program to crash the process with a segfault. The function is reachable through the operator when both operands are objects.

jq is a command-line JSON processor. In 1.8.1 and earlier, when decNumberFromString is given a number literal of INTMAX-1 (2147483646) digits, the D2U() macro overflows during signed-int arithmetic. The wrapped negative value bypasses the heap-allocation size check, causes the function to use a 30-byte stack buffer, and then writes ≈715 million 16-bit units (≈1.4 GiB) at an offset 1.43 GiB below the stack frame. The written content is fully attacker-controlled (the parsed decimal digits, packed 3-per-unit).

jq is a command-line JSON processor. In 1.8.1 and earlier, Top-level jq programs loaded from a file with -f are truncated at the first embedded NUL byte on current upstream HEAD. A crafted filter file such as . followed by \x00 and arbitrary suffix compiles and executes as only the prefix before the NUL. This leaves jq with a post-CVE-2026-33948 prefix/full-buffer mismatch on the compilation path even though the JSON parser path has already been fixed.

jq is a command-line JSON processor. In 1.8.1 and earlier, jvcontains recurses into nested arrays/objects with no depth limit. With a sufficiently nested input structure (built programmatically with reduce, since the JSON parser caps at depth 10000), the C stack is exhausted.

jq is a command-line JSON processor. In 1.8.1 and earlier, jq accepts embedded NUL bytes in import paths at the jq-language level, but later resolves those paths through C string operations during module and data-file lookup. This creates a mismatch between the logical import string that policy or audit code may validate and the on-disk path that jq actually opens.