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TI-2026-26298 Aliases CVE-2026-33948

jq: Embedded-NUL Truncation in CLI JSON Input Path Causes Prefix-Only Validation of Malformed Input

Priority MEDIUM 48CWE-170Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Attack requirements
Present
Impact type
—
Confidentiality · integrity · availability
None · Low · None
Fix status
Partial Red Hat: 1 fixed, 4 without a fix

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and Red Hat.

Summary

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.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00256 17th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Partial jq (jqlang): 6374ae0Red Hat: 1 advisoryRed Hat: 1 fixed, 4 without a fix

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
jqlangjqbefore 6374ae06374ae0Patch availableCNA
  • jq Vendorjqlang Affected before 6374ae0 Fixed in 6374ae0 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:jqlang:jq:*:*:*:*:*:*:*:*before 1.8.2Vulnerablejqlang
  • cpe:2.3:a:jqlang:jq:*:*:*:*:*:*:*:* Versions before 1.8.2 Vulnerable ·jqlang

Remediation

  • Fix · CNA jq (jqlang) Fixed in 6374ae0

Red Hat 1 advisory

  • RHSA-2026:8579 Released 2026-04-16 · Red Hat rating Important
    Red Hat Hardened Images RPMs bug fix and enhancement update
    • Red Hat Hardened Images jq-1.8.1-3.hum1@aarch64, jq-1.8.1-3.hum1@src, jq-1.8.1-3.hum1@x86_64 +2

Vendor assessments

Red Hat

Red Hat rating: Low. Red Hat's page for this CVE →

ProductStatusPlan or fix
Red Hat Enterprise Linux 10AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 8AffectedNo fix yet: Fix deferred
Red Hat Enterprise Linux 9AffectedNo fix yet: Fix deferred
Red Hat OpenShift Container Platform 4AffectedNo fix yet: Fix deferred
Red Hat Hardened ImagesFixed RHSA-2026:8579

Timeline

  1. 2026-10-02 Threatist record created from CVE-2026-33948

References

Exploit 1

Patch 1

  • TI-2026-24844 jq: Integer overflow in jvp_string_append() allows Heap-based Buffer Overflow CVSS 3.1HIGH 8.2
  • TI-2025-30431 AddressSanitizer: stack-buffer-overflow in jq_fuzz_execute (jv_string_vfmt) CVSS 4.0HIGH 7.7
  • TI-2023-26962 decToString in decNumber/decNumber.c in jq 88f01a7 has a one-byte out-of-bounds write via… CVSS 3.1HIGH 7.5
  • TI-2026-28834 jq: Out-of-Bounds Read in jv_parse_sized() Error Formatting for Non-NUL-Terminated Counted Buffers CVSS 4.0MEDIUM 6.9
  • TI-2024-35799 Type confusion in jqlang jq CVSS 3.1HIGH 8.1
  • TI-2026-36743 jq --rawfile invalid-state reuse after String too long causes heap-buffer-overflow CVSS 3.1HIGH 7.1
See all 21 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences