tomojitakasu RTKLIB up to 2.4.3 src/rinex.c readrnxobsb heap-based overflow

Summaryinfo

A vulnerability was found in tomojitakasu RTKLIB up to 2.4.3. It has been declared as critical. This affects the function readrnxobsb of the file src/rinex.c. Such manipulation leads to heap-based overflow. This vulnerability is referenced as CVE-2026-56789. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in tomojitakasu RTKLIB up to 2.4.3. It has been rated as critical. Affected by this issue is the function readrnxobsb of the file src/rinex.c. The manipulation with an unknown input leads to a heap-based overflow vulnerability. Using CWE to declare the problem leads to CWE-122. A heap overflow condition is a buffer overflow, where the buffer that can be overwritten is allocated in the heap portion of memory, generally meaning that the buffer was allocated using a routine such as malloc(). Impacted is availability. CVE summarizes:

RTKLIB through 2.4.3 contains a heap buffer overflow vulnerability in the readrnxobsb function in src/rinex.c that allows attackers to trigger memory corruption by failing to clamp satellite count values from RINEX epoch headers. Attackers can craft malicious RINEX files declaring more than 64 satellites per epoch to cause heap buffer overflow writes and out-of-bounds stack reads, crashing RTKLIB-based applications including rnx2rtkp and RTKPOST.

The weakness was published by FuzzingLabs as 796. The advisory is available at github.com. This vulnerability is handled as CVE-2026-56789 since 06/23/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/26/2026).

There is no information about possible countermeasures known. It may be suggested to replace the affected object with an alternative product.

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Productinfo

Vendor

• tomojitakasu

Name

• RTKLIB

Version

• 2.4.0
• 2.4.1
• 2.4.2
• 2.4.3

Website

• Product: https://github.com/tomojitakasu/RTKLIB/

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