Junglewise Threat Intelligence

CVE-2026-56787: RTKLIB off-by-one error in decode_ssr3 function

CVE-2026-56787 · Severity: medium · CVSS 6.5 · Published 2026-06-25

Technologies: Tomoji Takasu RTKLIB. Vendors: Tomoji Takasu.

Executive brief

RTKLIB is an open-source library used for high-precision satellite positioning in GPS/GNSS receivers and base stations. A vulnerability in how the software processes correction data allows a remote attacker to send a specially crafted message that can crash the system. This could lead to a loss of positioning services for mobile rovers or the failure of permanent reference stations (CORS) used in surveying and navigation.

Technical details

An off-by-one error exists in the `decode_ssr3` function within `src/rtcm3.c` at line 1446. The vulnerability is triggered when processing RTCM3 State Space Representation (SSR) messages containing attacker-controlled signal mode fields. By sending a crafted SSR correction stream via NTRIP or serial connections, a remote attacker can cause an out-of-bounds read leading to a global buffer overflow. This results in a denial-of-service (DoS) condition, crashing RTKLIB-based rovers or CORS servers. As of the advisory date, the issue affects all versions through 2.4.3.

Affected products

  • tomojitakasu RTKLIB through 2.4.3

Timeline

  • 2026-06-09: disclosed: Issue reported on GitHub by researcher raefko (FuzzingLabs)
  • 2026-06-25: advisory: NVD and VulnCheck published advisory details

References

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