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Amazon Linux 2023 : jq, jq-devel (ALAS2023-2026-1815)
medium Nessus Plugin ID 319811
Synopsis
The remote Amazon Linux 2023 host is missing a security update.Description
It is, therefore, affected by multiple vulnerabilities as referenced in the ALAS2023-2026-1815 advisory.jq is a command-line JSON processor. An integer overflow vulnerability exists through version 1.8.1 within the jvp_string_append() and jvp_string_copy_replace_bad 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. (CVE-2026-32316)
jq is a command-line JSON processor. In versions 1.8.1 and below, functions jv_setpath(), jv_getpath(), and delpaths_sorted() in jq's src/jv_aux.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 MAX_PARSING_DEPTH (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. (CVE-2026-33947)
jq is a command-line JSON processor. Commits before 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b contain a vulnerability where CLI input parsing allows validation bypass via embedded NUL bytes. When reading JSON from files or stdin, jq uses strlen() to determine buffer length instead of the actual byte count from fgets(), causing it to truncate input at the first NUL byte and parse only the preceding prefix. This enables an attacker to craft input with a benign JSON prefix before a NUL byte followed by malicious trailing data, where jq validates only the prefix as valid JSON while silently discarding the suffix.
Workflows relying on jq to validate untrusted JSON before forwarding it to downstream consumers are susceptible to parser differential attacks, as those consumers may process the full input including the malicious trailing bytes. This issue has been patched by commit 6374ae0bcdfe33a18eb0ae6db28493b1f34a0a5b.
(CVE-2026-33948)
jq is a command-line JSON processor. In commits after 69785bf77f86e2ea1b4a20ca86775916889e91c9, the
_strindices builtin in jq's src/builtin.c passes its arguments directly to jv_string_indexes() without verifying they are strings, and jv_string_indexes() in src/jv.c relies solely on assert() checks that are stripped in release builds compiled with -DNDEBUG. This allows an attacker to crash jq trivially with input like _strindices(0), and by crafting a numeric value whose IEEE-754 bit pattern maps to a chosen pointer, achieve a controlled pointer dereference and limited memory read/probe primitive. Any deployment that evaluates untrusted jq filters against a release build is vulnerable. This issue has been patched in commit fdf8ef0f0810e3d365cdd5160de43db46f57ed03. (CVE-2026-39956)
jq is a command-line JSON processor. In commits before 2f09060afab23fe9390cce7cb860b10416e1bf5f, the jv_parse_sized() API in libjq accepts a counted buffer with an explicit length parameter, but its error- handling path formats the input buffer using %s in jv_string_fmt(), which reads until a NUL terminator is found rather than respecting the caller-supplied length. This means that when malformed JSON is passed in a non-NUL-terminated buffer, the error construction logic performs an out-of-bounds read past the end of the buffer. The vulnerability is reachable by any libjq consumer calling jv_parse_sized() with untrusted input, and depending on memory layout, can result in memory disclosure or process termination. The issue has been patched in commit 2f09060afab23fe9390cce7cb860b10416e1bf5f. (CVE-2026-39979)
jq is a command-line JSON processor. Before commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784, jq used MurmurHash3 with a hardcoded, publicly visible seed (0x432A9843) for all JSON object hash table operations, which allowed an attacker to precompute key collisions offline. By supplying a crafted JSON object (~100 KB) where all keys hashed to the same bucket, hash table lookups degraded from O(1) to O(n), turning any jq expression into an O(n2) operation and causing significant CPU exhaustion. This affected common jq use cases such as CI/CD pipelines, web services, and data processing scripts, and was far more practical to exploit than existing heap overflow issues since it required only a small payload. This issue has been patched in commit 0c7d133c3c7e37c00b6d46b658a02244fdd3c784. (CVE-2026-40164)
jq is a command-line JSON processor. In 1.8.1 and earlier, when decNumberFromString is given a number literal of INT_MAX-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).
(CVE-2026-43894)
jq is a command-line JSON processor. In 1.8.1 and earlier, unbounded recursion in jv_object_merge_recursive() allows a crafted jq program to crash the process with a segfault. The function is reachable through the * operator when both operands are objects. (CVE-2026-43896)
Tenable has extracted the preceding description block directly from the tested product security advisory.
Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.
Solution
Run 'dnf update jq --releasever 2023.12.20260608' or or 'dnf update --advisory ALAS2023-2026-1815 --releasever 2023.12.20260608' to update your system.See Also
https://alas.aws.amazon.com//AL2023/ALAS2023-2026-1815.html
https://alas.aws.amazon.com/faqs.html
https://explore.alas.aws.amazon.com/CVE-2026-32316.html
https://explore.alas.aws.amazon.com/CVE-2026-33947.html
https://explore.alas.aws.amazon.com/CVE-2026-33948.html
https://explore.alas.aws.amazon.com/CVE-2026-39956.html
https://explore.alas.aws.amazon.com/CVE-2026-39979.html
https://explore.alas.aws.amazon.com/CVE-2026-40164.html
Plugin Details
Severity: Medium
ID: 319811
File Name: al2023_ALAS2023-2026-1815.nasl
Version: 1.1
Type: Local
Agent: unix
Published: 6/8/2026
Updated: 6/8/2026
Supported Sensors: Frictionless Assessment AWS, Frictionless Assessment Agent, Nessus Agent, Agentless Assessment, Continuous Assessment, Nessus
Risk Information
VPR
Risk Factor: Medium
Score: 5.0
CVSS v2
Risk Factor: Medium
Base Score: 6.4
Temporal Score: 5
Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:N/A:P
CVSS Score Source: CVE-2026-39979
CVSS v3
Risk Factor: Medium
Base Score: 6.5
Temporal Score: 5.9
Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L
Temporal Vector: CVSS:3.0/E:P/RL:O/RC:C
CVSS v4
Risk Factor: Medium
Base Score: 6.9
Threat Score: 5.5
Threat Vector: CVSS:4.0/E:P
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N
Vulnerability Information
CPE: p-cpe:/a:amazon:linux:jq, p-cpe:/a:amazon:linux:jq-devel, p-cpe:/a:amazon:linux:jq-debugsource, p-cpe:/a:amazon:linux:jq-debuginfo, cpe:/o:amazon:linux:2023
Required KB Items: Host/local_checks_enabled, Host/AmazonLinux/release, Host/AmazonLinux/rpm-list
Exploit Available: true
Exploit Ease: Exploits are available
Patch Publication Date: 6/8/2026
Vulnerability Publication Date: 11/13/2025
Reference Information
CVE: CVE-2026-32316, CVE-2026-33947, CVE-2026-33948, CVE-2026-39956, CVE-2026-39979, CVE-2026-40164, CVE-2026-43894, CVE-2026-43896
IAVB: 2025-B-0188