Strix
75.6K

CVE-2026-39979

MEDIUMCVSS 6.5/10EPSS 0.56%

Last modified

CVE-2026-39979 is a medium-severity vulnerability rated 6.5/10 on the CVSS scale. 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. EPSS estimates a 0.56% chance of exploitation in the next 30 days.

Description

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.

Metrics

CVSS 3.1
6.5/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L

CVSS 4.0
6.9/10

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/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS Probability
0.56%

46.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

VendorProductVersions
JqlangJq< 1.8.2
RedhatAi Inference Server>= 3.2.0, < 3.2.2
RedhatAi Inference Server>= 3.3.0, < 3.3.5
RedhatAnsible Automation Platform2.0
RedhatCeph Storage4.0
RedhatCodeready Linux Builder8.0
RedhatCodeready Linux Builder9.0
RedhatCodeready Linux Builder10.0
RedhatCodeready Linux Builder Eus9.4
RedhatCodeready Linux Builder Eus9.6
RedhatCodeready Linux Builder Eus10.0
RedhatHardened ImagesAll versions
RedhatOpenshift Ai>= 3.4, < 3.4.3
RedhatOpenshift Container Platform>= 4.12, < 4.12.92
RedhatOpenshift Container Platform>= 4.13, < 4.13.68
RedhatOpenshift Container Platform>= 4.14, < 4.14.68
RedhatOpenshift Container Platform>= 4.15, < 4.15.65
RedhatOpenshift Container Platform>= 4.16, < 4.16.64
RedhatOpenshift Container Platform>= 4.17, < 4.17.55
RedhatOpenshift Container Platform>= 4.18, < 4.18.44
RedhatOpenshift Container Platform>= 4.19, < 4.19.33
RedhatEnterprise Linux8.0
RedhatEnterprise Linux9.0
RedhatEnterprise Linux10.0
RedhatEnterprise Linux Aus8.4
RedhatEnterprise Linux Aus8.6
RedhatEnterprise Linux Eus8.4
RedhatEnterprise Linux Eus9.4
RedhatEnterprise Linux Eus9.6
RedhatEnterprise Linux Eus10.0
RedhatEnterprise Linux Tus8.6
RedhatEnterprise Linux Tus8.8
RedhatEnterprise Linux Update Services For Sap Solutions8.6
RedhatEnterprise Linux Update Services For Sap Solutions8.8
RedhatEnterprise Linux Update Services For Sap Solutions9.0
RedhatEnterprise Linux Update Services For Sap Solutions9.2

References

Timeline

Published
Last Modified
Status
Analyzed

Frequently Asked Questions

What is CVE-2026-39979?
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.
How severe is CVE-2026-39979?
CVE-2026-39979 has a CVSS score of 6.5/10 (MEDIUM severity). The EPSS model estimates a 0.56% probability of exploitation in the next 30 days.
How do I fix CVE-2026-39979?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

How Strix Helps

Related CVEs from 2026

View all 2026CVEs →

Are you affected by CVE-2026-39979?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST