GoBGP has a panic in AdjRib.Update via malformed BGP Update message (Nil Pointer Dereference)

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

7.5 · CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

EPSS

• CVE-2026-42285: 0.42% estimated exploitation activity in the next 30 days; percentile 36.18 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Summary Remote Denial of Service (DoS) via Nil Pointer Dereference in BGP Update Processing An unauthenticated remote BGP peer can trigger a fatal panic in GoBGP by sending a specially crafted BGP UPDATE message. When the server receives a message with inconsistent attribute lengths, it improperly handles the internal state transition to a "withdraw" action, leading to a nil pointer dereference in the AdjRib.Update function. This causes the entire GoBGP process to crash, resulting in a complete loss of service availability. Details The vulnerability originates in the interaction between the BGP message decoding logic and the Adj-RIB table management. Triggering Condition: When a BGP UPDATE message contains attributes that fail validation (e.g., "attribute value length is short"), GoBGP logs a warning: the received Update message was treated as withdraw. Code Path: The message reaches github.com/osrg/gobgp/v4/pkg/server.(peer).handleUpdate. Due to the malformed attributes, the message…

Published by the source

5 May 2026, 20:57 UTC

Last modified by the source

8 May 2026, 20:42 UTC

Source last checked

26 Oct 2026, 15:20 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-p3w2-64xm-833j

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# Patch Next advisory brief: CVE-2026-42285

Advisory: GoBGP has a panic in AdjRib.Update via malformed BGP Update message (Nil Pointer Dereference)
IDs: CVE-2026-42285, GHSA-p3w2-64xm-833j
Record: https://patchnext.com/advisories/cve-2026-42285 (revision 1, source checked 26 Oct 2026, 15:20 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 7.5)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: github.com/osrg/gobgp/v4 4.5.0. A vendor fix does not mean a deployment is fixed.

## Affected components
- Go github.com/osrg/gobgp/v4: affected >= 4.4.0, <= 4.4.0; fixed in 4.5.0

## Suggested inspection (read-only)
- Go github.com/osrg/gobgp/v4: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on github.com/osrg/gobgp/v4.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-p3w2-64xm-833j (GitHub-reviewed advisory GHSA-p3w2-64xm-833j lists affected ranges: Go github.com/osrg/gobgp/v4 >=4.4.0 <=4.4.0)

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