CVE-2026-56789

RTKLIB 2.4.3 - Heap Buffer Overflow and Stack Read via Oversized RINEX Epoch Satellite Count

7.1 High

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.

Attack profile

How easy it is to exploit

Attack vector: Network
Complexity: Low
Privileges needed: None
User interaction: Passive

What an attacker can affect

Confidentiality: None
Integrity: None
Availability: High

Exploit likelihood

0.42%Up 0.2 points since Jun 26, 2026

What each source reports

CVE List Score used 7.1

RTKLIB 2.4.3 - Heap Buffer Overflow and Stack Read via Oversized RINEX Epoch Satellite Count

Record: CVE-2026-56789
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness: CWE-122
Updated: 2026-11-02

EUVDEUVD-2026-39531 7.1

Record: EUVD-2026-39531
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
Updated: 2026-11-02

GitHub AdvisoriesGHSA-3fqf-8h5x-pq8x 7.1

RTKLIB through 2.4.3 contains a heap buffer overflow vulnerability in the readrnxobsb function in...

Record: GHSA-3fqf-8h5x-pq8x
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness: CWE-122
Updated: 2026-11-02

NVD 7.1

Record: CVE-2026-56789
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Weakness: CWE-122
Updated: 2026-11-02

OSVDEBIAN-CVE-2026-56789 7.1

Record: DEBIAN-CVE-2026-56789
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Updated: 2026-11-02

OSVUBUNTU-CVE-2026-56789 7.1

Record: UBUNTU-CVE-2026-56789
CVSS 4.0: 7.1 HighCVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N
CVSS 3.1: 6.5 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`rtklib` Debian:12	All versions, plus listed versions 2.4.3.b34+dfsg-1	None known
`rtklib` Debian:13	All versions, plus listed versions 2.4.3.b34+dfsg-1	None known
`rtklib` Debian:14	All versions, plus listed versions 2.4.3.b34+dfsg-1	None known
`rtklib` Ubuntu:18.04:LTS	All versions, plus listed versions 2.4.3+dfsg1-1	None known
`rtklib` Ubuntu:20.04:LTS	All versions, plus listed versions 2.4.3+dfsg1-12.4.3+dfsg1-2.12.4.3+dfsg1-2.1build1	None known
`rtklib` Ubuntu:22.04:LTS	All versions, plus listed versions 2.4.3+dfsg1-2.1build12.4.3.b34+dfsg-1	None known
`rtklib` Ubuntu:24.04:LTS	All versions, plus listed versions 2.4.3.b34+dfsg-12.4.3.b34+dfsg-1build12.4.3.b34+dfsg-1build2	None known
`rtklib` Ubuntu:25.10	All versions, plus listed versions 2.4.3.b34+dfsg-1build2	None known
`rtklib` Ubuntu:26.10	All versions, plus listed versions 2.4.3.b34+dfsg-1build3	None known
`rtklib` Ubuntu:26.04:LTS	All versions, plus listed versions 2.4.3.b34+dfsg-1build22.4.3.b34+dfsg-1build3	None known

History

History
Recorded	Changed	Sources
Nov 2, 2026	aliases, published	EUVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-56789 is a high vulnerability (CVSS 7.1) in Rtklib, published June 25, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.42%, the 36th percentile. No source names a fixed version.