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CVE-2026-5122· NVD / CVE Program· CNA VulDB

osrg GoBGP BGP OPEN Message bgp.go DecodeFromBytes access control

A security flaw has been discovered in osrg GoBGP up to 4.3.0. This affects the function DecodeFromBytes of the file pkg/packet/bgp/bgp.go of the component BGP OPEN Message Handler. Performing a manipulation of the argument domainNameLen results in improper access controls. The attack may be initiated remotely. A high degree of complexity is needed for the attack. The exploitability is reported as difficult. The patch is named 2b09db390a3d455808363c53e409afe6b1b86d2d. It is suggested to install a patch to address this issue.

MediumCVSS 6.3 · v4.0—No exploit Fix available

Noroxi analysis

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Published
Mar 30, 2026
Updated
Jun 17, 2026
EPSS
0.5% · 38th percentile
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Report tools

JSON

Action score

25

Monitor

Low priority for now.

CVSS
25 / 40 · 6.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · VulDB
6.3
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:X

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Affected systems

VendorProduct
osrggobgp

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • osrg gobgpbefore 4.4.0

Versions reported by the vendor

Affected version ranges reported by the assigning authority (VulDB). Independent of NVD's CPE analysis and usually ahead of it.

  • osrg GoBGP

    • 4.0, 4.1, 4.2, 4.3.0affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12gobgpall versions—
Debian:14gobgpbefore 4.4.0-14.4.0-1

Same product

osrg: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-43973An issue was discovered in GoBGP before 3.35.0.
    39Monitor
  • CVE-2026-42285GoBGP: Panic in AdjRib.Update via malformed BGP Update message (Nil Pointer Dereference)
    30Monitor
  • CVE-2026-41643GoBGP: Remote Denial of Service (Panic) in UpdatePathAttrs4ByteAs via Malformed BGP UPDATE
    30Monitor
  • CVE-2026-41642GoBGP: Remote Denial of Service (Panic) via Malformed Well-known Path Attribute
    30Monitor
  • CVE-2026-37461An out-of-bounds read in the ParseIP6Extended function (/bgp/bgp.go) of gobgp v4.3.0 allows attackers to cause a Denial of Service (DoS) via
    30Monitor
  • CVE-2026-30405An issue in GoBGP gobgpd v.4.2.0 allows a remote attacker to cause a denial of service via the NEXT_HOP path attribute
    30Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
debian:gobgp4.4.0-1 · Debian:14Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-51240 days apartosrg GoBGP BGP Header bgp.go BGPHeader.DecodeFromBytes access control
    25Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • Special conditions such as timing or configuration are required.

If successful

Confidentiality
Integrity
Availability
Attack vector
Network
Attack complexity
High
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-266 · Incorrect Privilege Assignment

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records