CVE-2026-41642: GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language

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HIGH 7.5REMOTEDOWNGRADE

CVE-2026-41642 is a high-severity flaw (CVSS 7.5) affecting gobgp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. In version 4.3.0, a remote Denial of Service (DoS) vulnerability exists in GoBGP due to a nil pointer dereference. When a malformed BGP UPDATE message contains an unrecognized Path Attribute marked as "Well-known," the daemon fails to interrupt the message handling flow. This results in an illegal memory access and a full process crash (panic). Th

Why this priority

High severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 57%)
CISA exploited list	No
Weakness	CWE-476
Published	2026-05-07
Last modified	2026-10-26

Publisher (CNA): GitHub, Inc. · Vendor: osrg

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-07 12:16 UTCPublished CVE record published
2026-10-26 22:10 UTCUpdated Record last modified

osrg gobgp DOWNGRADE

Affected: 4.3.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 4.3.0

1. Check installed version

apt-cache policy gobgp || rpm -q gobgp || gobgp --version

2. No fixed release: DOWNGRADE to a release before 4.3.0 (Debian / Ubuntu)

apt-cache madison gobgp sudo apt install gobgp=<VERSION_BEFORE_4.3.0> sudo apt-mark hold gobgp

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list gobgp sudo dnf downgrade gobgp-<VERSION_BEFORE_4.3.0> sudo dnf versionlock add gobgp

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-41642?

gobgp: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2026-41642 being exploited?

CVE-2026-41642 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-41642 affect?

CVE-2026-41642 affects gobgp. Severity is high (CVSS 7.5). GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. In version 4.3.0, a remote Denial of Service (DoS) vulnerability exists in GoBGP due to a nil pointer dereference. When a malformed BGP UPD

How urgent is CVE-2026-41642?

Priority 47/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2026-42285 HIGH 7.5 DOWNGRADE GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language
CVE-2026-41643 HIGH 7.5 UPGRADE GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language
CVE-2026-7736 HIGH 7.3 UPGRADE A vulnerability was determined in osrg GoBGP up to 4.3.0
CVE-2026-7735 HIGH 7.3 UPGRADE A vulnerability was found in osrg GoBGP up to 4.3.0
CVE-2026-7737 MEDIUM 5.3 UPGRADE A vulnerability was identified in osrg GoBGP up to 4.3.0

References

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