How severe is CVE-2026-56786?

CVE-2026-56786 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2026-56786 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-56786?

CVE-2026-56786 affects Rtklib. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-56786?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

Does CVE-2026-56786 have an EU (EUVD) identifier?

Yes. CVE-2026-56786 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39528.

When was CVE-2026-56786 published?

CVE-2026-56786 was published on 2026-06-25 and last updated on 2026-06-26.

CVE-2026-56786

CVE-2026-56786 is a critical-severity vulnerability in Rtklib with a CVSS 3.x base score of 9.8. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-787.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v4: 9.3
EPSS exploit prediction: 0% (34th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-39528
Weakness: CWE-787
Affected product: Rtklib
Published: 2026-06-25
Last modified: 2026-06-26

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.

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.
How severe is CVE-2026-56786?: CVE-2026-56786 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2026-56786 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (34th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-56786?: CVE-2026-56786 affects Rtklib. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-56786?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
Does CVE-2026-56786 have an EU (EUVD) identifier?: Yes. CVE-2026-56786 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-39528.
When was CVE-2026-56786 published?: CVE-2026-56786 was published on 2026-06-25 and last updated on 2026-06-26.

References

Affected products (1)

cpe:2.3:a:rtklib:rtklib:*:*:*:*:*:*:*:*

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