Njs
CVE-2019-11839
CRITICAL
Vulnerability Assessment
| Weakness |
CWE
ASVS 5.0
V15 - Secure Coding and Architecture Bounds checking, write limits
MITRE ATT&CK
2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. |
| Impact | CVSS score of 9.8 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, no user interaction not required. Public proof-of-concept exploit code is available. |
| Exploit ScenarioDerived | A remote attacker could write data beyond allocated buffer boundaries leading to code execution or crashes by sending crafted requests to the affected application. No authentication is required to exploit this vulnerability. |
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Alert meAnalysisAI
njs through 0.3.1, used in NGINX, has a heap-based buffer overflow in Array.prototype.push after a resize, related to njs_array_prototype_push in njs/njs_array.c, because of njs_array_expand size. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available and no vendor patch available.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).
Affects your stack
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Checking this CVE against your own stacks and servers is part of the Basic plan and up.
Technical ContextAI · show details
This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. njs through 0.3.1, used in NGINX, has a heap-based buffer overflow in Array.prototype.push after a resize, related to njs_array_prototype_push in njs/njs_array.c, because of njs_array_expand size mishandling. Affected products include: F5 Njs. Version information: through 0.3.1.
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- Exploit and PoC references, threat intelligence from 22 sources
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Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
DescriptionNVD
njs through 0.3.1, used in NGINX, has a heap-based buffer overflow in Array.prototype.push after a resize, related to njs_array_prototype_push in njs/njs_array.c, because of njs_array_expand size mishandling.
Threat Intelligence Overview
NVD
CVE.org
EPSS
GitHub
How this decision was reached
The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.
What every action level means
SSVC AssessmentENISA
Priority Score
Attack Technique
A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.
Memory corruption occurs when a program writes data beyond the boundaries of allocated memory regions or accesses memory in unintended ways, violating the integrity of the process's address space.
Affected Products (CPE)NVD
Nginx NJS v0.7.2 was discovered to contain a heap-use-after-free bug caused by illegal memory copy in the function njs_j
Nginx NJS v0.7.3 was discovered to contain a stack overflow in the function njs_default_module_loader at /src/njs/src/nj
nginx njs 0.7.2 is affected suffers from Use-after-free in njs_function_frame_alloc() when it try to invoke from a resto
njs through 0.3.3, used in NGINX, has a buffer over-read in nxt_utf8_decode in nxt/nxt_utf8.c. Rated critical severity (
njs through 0.3.1, used in NGINX, has a heap-based buffer overflow in njs_function_native_call in njs/njs_function.c. Ra
njs through 0.3.1, used in NGINX, has a heap-based buffer over-read in nxt_utf8_decode in nxt/nxt_utf8.c. Rated critical
njs through 0.3.1, used in NGINX, has a heap-based buffer overflow in nxt_utf8_encode in nxt_utf8.c. Rated critical seve
njs through 0.3.1, used in NGINX, has a heap-based buffer overflow in Array.prototype.splice after a resize, related to
Nginx NJS v0.7.4 was discovered to contain an out-of-bounds read via njs_scope_value at njs_scope.h. Rated critical seve
njs through 0.4.3, used in NGINX, has a use-after-free in njs_json_parse_iterator_call in njs_json.c. Rated high severit
Nginx NJS v0.7.10 was discovered to contain a segmentation violation via the function njs_lvlhsh_find at src/njs_lvlhsh.
Nginx NJS v0.7.10 was discovered to contain a segmentation violation via the function njs_dump_is_recursive at src/njs_v
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