CVE-2026-56786Public exploitNetwork attack vector

Memory corruption via unclamped RTCM3 descriptor lengths

Published Jun 25, 2026 · Updated Jun 25, 2026

Out-of-bounds writes in RTKLIB 2.4.3 and earlier allow remote attackers to corrupt memory via crafted RTCM3 type-1033 streams. decode_type1033 passes five untrusted 8-bit lengths to strncpy and terminator writes targeting fixed 64-byte rtcm_t descriptor fields. Control of an NTRIP or serial correction stream is required; corruption can crash a consumer or alter adjacent rtcm_t state.

CVSS severity9.3
Critical
EPSS probability0.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds writes in RTKLIB 2.4.3 and earlier allow remote attackers to corrupt memory via crafted RTCM3 type-1033 streams. decode_type1033 passes five untrusted 8-bit lengths to strncpy and terminator writes targeting fixed 64-byte rtcm_t descriptor fields. Control of an NTRIP or serial correction stream is required; corruption can crash a consumer or alter adjacent rtcm_t state.

The record

CVE
CVE-2026-56786
Published
Jun 25, 2026
Updated
Jun 25, 2026
Vendor
Tomoji Takasu
Product
RTKLIB
Classifications
CWE-787, T1203
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jun 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 25, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <=2.4.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Tomoji Takasu · RTKLIBversion=0 <=2.4.3

Published CVSS scores

9.3VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
9.8VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-787Out-of-bounds Write
T1203Exploitation for Client Execution

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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