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CVE-2026-67216

cJSON cJSON_Compare Exponential Complexity Denial of Service

8.2 HighFix available

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
None
Availability
High

Exploit likelihood

0.65%Up 0.3 points since Jul 30, 2026
90%50%10%1%

What each source reports

CVE List Score used 8.2

cJSON cJSON_Compare Exponential Complexity Denial of Service

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Record
CVE-2026-67216
CVSS 4.0
8.2 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-407
Updated
2026-11-02
EUVDEUVD-2026-50328 8.2

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Record
EUVD-2026-50328
CVSS 4.0
8.2 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-ff2v-f99f-wm3f 8.2

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When...

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Record
GHSA-ff2v-f99f-wm3f
CVSS 4.0
8.2 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/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
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-407
Updated
2026-11-02
NVD 8.2

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Record
CVE-2026-67216
CVSS 4.0
8.2 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/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
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness
CWE-407
Updated
2026-11-02
OSV 8.2

cJSON cJSON_Compare Exponential Complexity Denial of Service

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Record
CVE-2026-67216
CVSS 4.0
8.2 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Weakness
CWE-407
Updated
2026-11-02
OSVDEBIAN-CVE-2026-67216 7.5

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Record
DEBIAN-CVE-2026-67216
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
Show 4 moreShow less
OSVUBUNTU-CVE-2026-67216 8.2

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Record
UBUNTU-CVE-2026-67216
CVSS 4.0
8.2 HighCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS 3.1
5.9 MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H
Updated
2026-11-02
OSVAZL-94407 No score

CVE-2026-67216 affecting package apparmor 3.1.7-1

cJSON through 1.7.19 contains an inefficient algorithmic complexity flaw in cJSON_Compare(). When comparing objects, the function recurses into each shared subtree twice, once in each direction, with no depth guard, making the running time exponential in nesting depth. A small, deeply nested document of a few hundred bytes (depth around 40) compared for equality consumes hours of CPU, and the cost roughly doubles with each additional level of nesting. An application that calls cJSON_Compare() on attacker-influenced JSON that is structurally equal to a reference document is exposed to a denial-of-service condition.

Record
AZL-94407
Updated
2026-11-05
OSVROOT-OS-ALPINE-321-CVE-2026-67216 No score

CVE-2026-67216 in cjson - Patched by Root

Root has patched CVE-2026-67216 in the cjson package for Root:Alpine:3.21. Multiple fixed versions available.

Record
ROOT-OS-ALPINE-321-CVE-2026-67216
Updated
2026-11-02
OSVROOT-OS-ALPINE-323-CVE-2026-67216 No score

CVE-2026-67216 in cjson - Patched by Root

Root has patched CVE-2026-67216 in the cjson package for Root:Alpine:3.23. Multiple fixed versions available.

Record
ROOT-OS-ALPINE-323-CVE-2026-67216
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
apparmor
Azure Linux:3
through 3.1.7-1 None known
cjson
Debian:12
All versions, plus listed versions
1.7.15-11.7.15-1+deb12u11.7.15-1+deb12u21.7.15-1+deb12u31.7.15-1+deb12u4
Show 11 moreShow less
1.7.16-11.7.16-21.7.17-11.7.17-21.7.18-11.7.18-21.7.18-31.7.18-3.11.7.18-41.7.19-11.7.19-2
None known
cjson
Debian:13
All versions, plus listed versions
1.7.18-3.11.7.18-3.1+deb13u11.7.18-41.7.19-11.7.19-2
None known
cjson
Debian:14
All versions, plus listed versions
1.7.18-3.11.7.18-41.7.19-11.7.19-2
None known
cjson
Root:Alpine:3.21
before 1.7.19-r00072
1.7.19-r000721.7.19-r00071
rootio-cjson
Root:Alpine:3.21
before 1.7.19-r00072
1.7.19-r000721.7.19-r00071
cjson
Root:Alpine:3.23
before 1.7.19-r10071
1.7.19-r100711.7.19-r100741.7.19-r100721.7.19-r10073
rootio-cjson
Root:Alpine:3.23
before 1.7.19-r10071
1.7.19-r100711.7.19-r100741.7.19-r100721.7.19-r10073
iperf3
Ubuntu:Pro:16.04:LTS
All versions, plus listed versions
3.0.11-13.0.11-1ubuntu0.1~esm13.0.11-1ubuntu0.1~esm2
None known
mapcache
Ubuntu:16.04:LTS
All versions, plus listed versions
1.4.0-31.4.0-4
None known
Show 19 moreShow less
Affected packages
PackageAffectedFixed
iperf3
Ubuntu:Pro:18.04:LTS
All versions, plus listed versions
3.1.3-13.1.3-1ubuntu0.1~esm1
None known
mapcache
Ubuntu:18.04:LTS
All versions, plus listed versions
1.6.0-21.6.1-1
None known
cjson
Ubuntu:Pro:20.04:LTS
All versions, plus listed versions
1.7.10-1.11.7.10-1.1ubuntu0.1~esm1
None known
iperf3
Ubuntu:Pro:20.04:LTS
All versions, plus listed versions
3.6-23.7-13.7-23.7-33.7-3ubuntu0.1~esm13.7-3ubuntu0.1~esm2
None known
mapcache
Ubuntu:20.04:LTS
All versions, plus listed versions
1.8.0-11.8.0-1build21.10.0-1
None known
mapcache
Ubuntu:22.04:LTS
All versions, plus listed versions
1.10.0-2build11.10.0-2build31.12.0-1
None known
cjson
Ubuntu:Pro:22.04:LTS
All versions, plus listed versions
1.7.14-11.7.15-11.7.15-1ubuntu0.1~esm21.7.15-1ubuntu0.11.7.15-1ubuntu0.1+esm1
None known
iperf3
Ubuntu:Pro:22.04:LTS
All versions, plus listed versions
3.9-13.9-1build13.9-1+deb11u1build0.22.04.13.9-1+deb11u1ubuntu0.1~esm13.9-1+deb11u1ubuntu0.1
None known
mapcache
Ubuntu:24.04:LTS
All versions, plus listed versions
1.14.0-21.14.0-2build11.14.0-2build21.14.0-4build11.14.0-4build2
None known
cjson
Ubuntu:Pro:24.04:LTS
All versions, plus listed versions
1.7.16-11.7.16-21.7.17-11.7.17-1ubuntu0.1~esm21.7.17-1ubuntu0.1~esm3
None known
iperf3
Ubuntu:Pro:24.04:LTS
All versions, plus listed versions
3.14-13.15-13.16-13.16-1build13.16-1build23.16-1ubuntu0.1~esm1
None known
cjson
Ubuntu:26.10
All versions, plus listed versions
1.7.19-2
None known
iperf3
Ubuntu:26.10
All versions, plus listed versions
3.20-23.20-2.13.20-2.1build1
None known
mapcache
Ubuntu:26.10
All versions, plus listed versions
1.14.1-3build21.16.0-11.16.0-1build1
None known
sail-ocaml
Ubuntu:26.10
All versions, plus listed versions
0.19.1+dfsg5-1build30.20.2+dfsg-1build1
None known
cjson
Ubuntu:26.04:LTS
All versions, plus listed versions
1.7.18-3.11.7.18-41.7.19-11.7.19-2
None known
iperf3
Ubuntu:26.04:LTS
All versions, plus listed versions
3.18-23.19.1-23.20-2
None known
mapcache
Ubuntu:26.04:LTS
All versions, plus listed versions
1.14.1-31.14.1-3build11.14.1-3build2
None known
sail-ocaml
Ubuntu:26.04:LTS
All versions, plus listed versions
0.19.1+dfsg5-10.19.1+dfsg5-1build20.19.1+dfsg5-1build3
None known

History

History
RecordedChangedSources
factsOSV
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-67216 is a high vulnerability (CVSS 8.2) in Cjson Project Cjson, published July 29, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.65%, the 51st percentile. Fixed in cjson 1.7.19-r00072.

References

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