CVE-2026-56786

Description

RTKLIB through 2.4.3 contains an out-of-bounds write vulnerability in decode_type1033 function that fails to clamp length counters to destination buffer size, allowing up to 191-byte overflow into fixed 64-byte descriptor fields. An attacker controlling an NTRIP or serial RTCM3 correction stream can craft a valid CRC-bearing type-1033 message to corrupt adjacent rtcm_t object members, potentially achieving arbitrary code execution or denial of service.

CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0042

Probability of exploitation

0.34%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

Weakness Type (CWE)

CWE-787 Out-of-bounds Write

Affected Products

Vendor	Product	Versions
rtklib	rtklib	< 2.4.3

References

Exploits

https://github.com/tomojitakasu/RTKLIB/issues/799

Other References

https://www.vulncheck.com/advisories/rtklib-out-of-bounds-write-in-decode-type1033-via-crafted-rtcm3-message

Frequently Asked Questions

What is CVE-2026-56786? +

RTKLIB through 2.4.3 contains an out-of-bounds write vulnerability in decode_type1033 function that fails to clamp length counters to destination buffer size, allowing up to 191-byte overflow into fixed 64-byte descriptor fields. An attacker controlling an NTRIP or serial RTCM3 correction stream can craft a valid CRC-bearing type-1033 message to corrupt adjacent rtcm_t object members, potentially achieving arbitrary code execution or denial of service. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-56786? +

CVE-2026-56786 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0042, placing it in the 0th percentile for exploitation probability.

What products are affected by CVE-2026-56786? +

CVE-2026-56786 affects products from rtklib, specifically: rtklib. Check the affected products table above for specific version ranges.

How do I check if I'm vulnerable to CVE-2026-56786? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

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