CVE-2026-16554
Integer Overflow Leading to Heap Buffer Overflow in cJSON
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service.
Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
5.1
Integer Overflow Leading to Heap Buffer Overflow in cJSON
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service.
Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
- Record
CVE-2026-16554- CVSS 4.0
- 5.1 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:L/SI:L/SA:L - Weakness
- CWE-190
- Updated
- 2026-11-02
EUVDEUVD-2026-49129
5.1
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service.
Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
- Record
EUVD-2026-49129- CVSS 4.0
- 5.1 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:L/SI:L/SA:L - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-qv6q-8g2j-w47g
5.1
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c...
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service.
Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
- Record
GHSA-qv6q-8g2j-w47g- CVSS 4.0
- 5.1 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:L/SI:L/SA:L/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
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-190
- Updated
- 2026-11-02
NVD
5.1
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service.
Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
- Record
CVE-2026-16554- CVSS 4.0
- 5.1 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:L/SI:L/SA:L/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
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-190
- Updated
- 2026-11-02
OSV
5.1
Integer Overflow Leading to Heap Buffer Overflow in cJSON
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service.
Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
- Record
CVE-2026-16554- CVSS 4.0
- 5.1 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:L/SI:L/SA:L - Weakness
- CWE-190
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-16554
7.8
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service. Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
- Record
DEBIAN-CVE-2026-16554- CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Show 5 moreShow less
OSVUBUNTU-CVE-2026-16554
5.1
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service. Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
- Record
UBUNTU-CVE-2026-16554- CVSS 4.0
- 5.1 Medium
CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:L/SI:L/SA:L - CVSS 3.1
- 7.8 High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVAZL-94184 No score
CVE-2026-16554 affecting package apparmor 3.1.7-1
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service.
Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
- Record
AZL-94184- Updated
- 2026-11-05
OSVAZL-94244 No score
CVE-2026-16554 affecting package libglvnd 1.7.0-3
cJSON library is vulnerable to an integer overflow in the print_string_ptr() function in cJSON.c on 32-bit platforms. The escape_characters counter, a 32-bit size_t, can wrap around when processing strings containing approximately 858,993,460 or more control characters, causing the output buffer to be allocated based on an underestimated length. When cJSON_PrintBuffered() is used with a pre-allocated buffer, the subsequent write loop overflows the heap allocation. An attacker supplying a crafted JSON string to an application using cJSON on a 32-bit platform can cause a heap buffer overflow, potentially leading to remote code execution, information disclosure, or denial of service.
Because project creator contact attempts were unsuccessful, the vulnerability has only been confirmed in version 1.7.19 but may also affect other versions.
- Record
AZL-94244- Updated
- 2026-11-05
OSVROOT-OS-ALPINE-321-CVE-2026-16554 No score
CVE-2026-16554 in cjson - Patched by Root
Root has patched CVE-2026-16554 in the cjson package for Root:Alpine:3.21. Multiple fixed versions available.
- Record
ROOT-OS-ALPINE-321-CVE-2026-16554- Updated
- 2026-11-02
OSVROOT-OS-ALPINE-323-CVE-2026-16554 No score
CVE-2026-16554 in cjson - Patched by Root
Root has patched CVE-2026-16554 in the cjson package for Root:Alpine:3.23. Multiple fixed versions available.
- Record
ROOT-OS-ALPINE-323-CVE-2026-16554- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
apparmorAzure Linux:3 |
through 3.1.7-1 | None known |
libglvndAzure Linux:3 |
through 1.7.0-3 | None known |
cjsonDebian: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 less1.7.16-11.7.16-21.7.17-11.7.17-21.7.18-11.7.18-21.7.18-31.7.18-3.11.7.18-41.7.19-11.7.19-2 |
None known |
cjsonDebian: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 |
cjsonDebian:14 |
All versions, plus listed versions 1.7.18-3.11.7.18-41.7.19-11.7.19-2 |
None known |
cjsonRoot:Alpine:3.21 |
before 1.7.19-r00072 | 1.7.19-r000721.7.19-r00071 |
rootio-cjsonRoot:Alpine:3.21 |
before 1.7.19-r00072 | 1.7.19-r000721.7.19-r00071 |
cjsonRoot:Alpine:3.23 |
before 1.7.19-r10071 | 1.7.19-r100711.7.19-r100741.7.19-r100721.7.19-r10073 |
rootio-cjsonRoot:Alpine:3.23 |
before 1.7.19-r10071 | 1.7.19-r100711.7.19-r100741.7.19-r100721.7.19-r10073 |
cjsonUbuntu:Pro:20.04:LTS |
All versions, plus listed versions 1.7.10-1.11.7.10-1.1ubuntu0.1~esm1 |
None known |
Show 4 moreShow less
| Package | Affected | Fixed |
|---|---|---|
cjsonUbuntu: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 |
cjsonUbuntu: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 |
cjsonUbuntu:26.10 |
All versions, plus listed versions 1.7.19-2 |
None known |
cjsonUbuntu:26.04:LTS |
All versions, plus listed versions 1.7.18-3.11.7.18-41.7.19-11.7.19-2 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| facts | OSV | |
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-16554 is a medium vulnerability (CVSS 5.1) in Cjson Project Cjson, published July 27, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.37%, the 30th percentile. Fixed in cjson 1.7.19-r00072.