CVE-2023-26819: cJSON 1.7.15 might allow a denial of service via a crafted JSON document such as {"a": true, "b": [ null,99999

Routine

LOW 2.9DOWNGRADE

CVE-2023-26819 is a low-severity flaw (CVSS 2.9) affecting cjson. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

cJSON 1.7.15 might allow a denial of service via a crafted JSON document such as {"a": true, "b": [ null,9999999999999999999999999999999999999999999999912345678901234567]}.

Why this priority

Public exploit reference

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	2.9 (Low)
Attack vector	Local
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 86%)
CISA exploited list	No
Weakness	CWE-440
Published	2025-04-19
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: cjson project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-04-19 22:15 UTCPublished CVE record published
2026-06-17 05:43 UTCUpdated Record last modified

cjson project cjson DOWNGRADE

Affected: 1.7.15

Fixed in: no fixed release known

Safe to downgrade to: a release before 1.7.15

1. Check installed version

apt-cache policy cjson || rpm -q cjson || cjson --version

2. No fixed release: DOWNGRADE to a release before 1.7.15 (Debian / Ubuntu)

apt-cache madison cjson sudo apt install cjson=<VERSION_BEFORE_1.7.15> sudo apt-mark hold cjson

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list cjson sudo dnf downgrade cjson-<VERSION_BEFORE_1.7.15> sudo dnf versionlock add cjson

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-26819?

cjson: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-26819 being exploited?

CVE-2023-26819 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-26819 affect?

CVE-2023-26819 affects cjson. Severity is low (CVSS 2.9). cJSON 1.7.15 might allow a denial of service via a crafted JSON document such as {"a": true, "b": [ null,9999999999999999999999999999999999999999999999912345678901234567]}.

How urgent is CVE-2023-26819?

Priority 19/100. Public exploit reference

Related CVEs

CVE-2026-16554 HIGH 7.8 DOWNGRADE cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit pla
CVE-2026-67215 HIGH 7.5 UPGRADE cJSON through 1.7.19 is vulnerable to uncontrolled recursion leading to stack exhaustion when an untrusted RFC
CVE-2026-67216 MEDIUM 5.9 UPGRADE cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare()
CVE-2026-67217 MEDIUM 5.3 UPGRADE cJSON through 1.7.19 applies RFC 6902 JSON Patch operations non-atomically in apply_patch() in cJSON_Utils.c
CVE-2025-57052 CRITICAL 9.8 UPGRADE cJSON 1.5.0 through 1.7.18 allows out-of-bounds access via the decode_array_index_from_pointer function in cJS

References

← Back to latest CVEs