CVE-2026-49837

MEDIUMPre-NVD 5.95.9
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This medium-severity CVE scores 5.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3% (24th percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source
5.9EG
EchelonGraph verdictMonitorRemediate within your standard update timelines (the SSVC decision on this page).
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0.3%CVSS: 5.9Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. Versions prior to 4.6.0 contain a BGP OPEN capability parsing issue where several concrete capability decoders may parse data from the full remaining capability buffer instead of the slice bounded by the declared capability length, CapLen. A malformed BGP OPEN message can cause bytes from a following capability to be interpreted as part of the current capability. The most security-relevant case is the 4-octet AS capability, where a capability with CapLen == 0 may cause the parser to read bytes from the following capability as the 4-octet AS value. This parsed value may later affect peer AS validation during BGP session establishment. Version 4.6.0 patches the issue.

CVSS v3
5.9
EG Score
5.9MEDIUMmedium confidence
EG Risk
27
EG Risk 27/100

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed (value × EchelonGraph’s weight)
Severity59% × 45%
The EG Score, 5.9 of 10.
Exploitation0.3% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.3%
EPSS %ILE
24th
KEV
Not listed

SSVC (CISA's decision table, applied by EchelonGraph)Track at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

July 9, 2026

Last Modified

September 16, 2026

Advisory Details (2)

Auto-updated Sep 10, 2026
Patch available. Sources: github, github_commit.
GitHub commit

commit f02ca397821f (osrg/gobgp)

Fix landed in osrg/gobgp commit f02ca397821f — awaiting tagged release

https://github.com/osrg/gobgp/commit/f02ca397821f6ca182ef4eb492c3cbc459552d7c
GitHub advisoryMentions a patch (unverified)

BGP OPEN capability parser may read capability values outside declared CapLen boundaries · Advisory · osrg/gobgp · GitHub

https://github.com/osrg/gobgp/security/advisories/GHSA-gjrg-jjr3-56cm

Vendor Advisories for CVE-2026-49837(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(5 across 5 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
gobgp2.25.0-2 ... 4.6.0-1 (27 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
gobgp3.10.0-1 ... 4.8.0-2~exp1 (27 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
gobgp3.36.0-2 ... 4.8.0-2~exp1 (12 versions)
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
gobgp3.36.0-2, 4.3.0-1, 4.4.0-1, 4.5.0-1, 4.5.0-1~bpo13+1
  • every version up to 4.6.0-1: fixed in 4.6.0-1
—
Go(1)
PackageVulnerable rangeFix by version rangeDependents
github.com/osrg/gobgp/v4—
  • every version up to 4.6.0: fixed in 4.6.0
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 35× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  2. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  3. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  4. 2026-10-12 15:59 UTCEG score recompute
  5. 2026-10-11 19:43 UTCEG score recompute
  6. 2026-10-11 16:57 UTCEG score recompute
  7. 2026-10-11 14:21 UTCEG score recompute
  8. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  9. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  10. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  11. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  12. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  13. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  14. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  15. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  16. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  17. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 24th percentile
  18. 2026-10-01 16:00 UTCEG score recompute
  19. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  20. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  21. 2026-09-28 09:56 UTCEG score recompute
  22. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  23. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  24. 2026-09-26 00:27 UTCEPSS rescoreEPSS 0.3% · 23rd percentile
  25. 2026-09-24 11:22 UTCEG score recompute
Show 20 more
  1. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  2. 2026-09-23 05:51 UTCEG score recompute
  3. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  4. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  5. 2026-09-18 05:26 UTCEG score recompute
  6. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  7. 2026-09-16 13:48 UTCEG score recompute
  8. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  9. 2026-09-15 16:35 UTCEG score recompute
  10. 2026-09-15 15:25 UTCEG score recompute
  11. 2026-09-14 08:50 UTCEG score recompute
  12. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  13. 2026-09-13 08:16 UTCEG score recompute
  14. 2026-09-12 03:18 UTCEG score recompute
  15. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.3% · 17th percentile
  16. 2026-09-10 22:20 UTCEG score recompute
  17. 2026-07-30 14:50 UTCEG score recompute
  18. 2026-07-26 12:14 UTCEG score recompute
  19. 2026-07-23 03:18 UTCEG score recompute
  20. 2026-07-09 23:46 UTCEG score recompute

Related CVEs(same product + same CWE)

Frequently asked(5)

What is CVE-2026-49837?
CVE-2026-49837 is a medium-severity vulnerability; its CVE record was published on July 9, 2026. GoBGP is an open source Border Gateway Protocol (BGP) implementation in the Go Programming Language. Versions prior to 4.6.0 contain a BGP OPEN capability parsing issue where several concrete capability decoders may parse data from the full remaining capability buffer instead of the slice bounded…
When was the CVE record for CVE-2026-49837 published?
The CVE record for CVE-2026-49837 was published on July 9, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of September 16, 2026; the record at its source may have been updated since.
Is CVE-2026-49837 actively exploited?
CVE-2026-49837 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.3% probability of exploitation in the next 30 days (24th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-49837?
CVE-2026-49837 has a CVSS base score of 5.9 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-49837?
A fix for CVE-2026-49837 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-49837 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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