CVE-2026-56099

MEDIUMNVD 5.35.3—
EchelonGraph scoreMEDIUM confidence

Score 5.3 from GitHub Security Advisory published 2026-06-18. NVD baseline CVSS 5.3; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, nvd
5.3EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 5.3Exploit: None knownExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

OpenBSD before commit 6a23123 (2026-06-18) contains an out-of-bounds read vulnerability in the mpls_do_error function within sys/netmpls/mpls_input.c that allows remote attackers to disclose kernel stack memory by sending crafted MPLS frames with 16 labels and no Bottom-of-Stack bit set.

CVSS v3
5.3
EG Score
5.3(medium)
EG Risk
39(Track)
EG Risk 39/100SSVC: Track

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
Severity53% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
41%
KEV
Not listed

Published

June 18, 2026

Last Modified

July 14, 2026

Advisory Details (3)

Auto-updated Jun 18, 2026
🔬 Proof of concept available. Upstream fix merged — awaiting tagged release. Sources: github_commit.
generic

OpenBSD mpls_do_error Kernel Stack Memory Disclosure via MPLS Input | Advisories | VulnCheck

https://www.vulncheck.com/advisories/openbsd-mpls-do-error-kernel-stack-memory-disclosure-via-mpls-input
generic🟡 PoC Available

OpenBSD - Remote Kernel MPLS Stack Disclosure · Argus Proof of Possession

https://pop.argus-systems.ai/advisory/adv-040.html
github_commit

commit 6a23123ec05f (openbsd/src)

Fix landed in openbsd/src commit 6a23123ec05f — awaiting tagged release

https://github.com/openbsd/src/commit/6a23123ec05f1eb29cfcaae0f3a468b2e1983cfd

Vendor Advisories for CVE-2026-56099(1)

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

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 5× in last 7d / 47× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. 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. Most recent first.

Showing the most recent 100 of 172 total refreshes for this CVE.

  1. 2026-09-11 14:53 UTCEPSS rescore
  2. 2026-09-10 09:35 UTCEPSS rescore
  3. 2026-09-08 22:01 UTCEPSS rescore
  4. 2026-09-07 16:01 UTCEPSS rescore
  5. 2026-09-06 13:47 UTCEPSS rescore
  6. 2026-09-04 05:07 UTCEPSS rescore
  7. 2026-09-02 14:12 UTCEPSS rescore
  8. 2026-09-01 13:54 UTCEPSS rescore
  9. 2026-09-01 04:40 UTCEPSS rescore
  10. 2026-08-30 20:54 UTCEG score recompute
  11. 2026-08-30 20:54 UTCGHSA enrichment
  12. 2026-08-30 19:17 UTCEPSS rescore
  13. 2026-08-30 01:22 UTCEPSS rescore
  14. 2026-08-28 21:41 UTCEPSS rescore
  15. 2026-08-27 14:25 UTCEPSS rescore
  16. 2026-08-26 14:46 UTCEPSS rescore
  17. 2026-08-25 13:49 UTCEPSS rescore
  18. 2026-08-24 23:51 UTCEG score recompute
  19. 2026-08-24 23:51 UTCGHSA enrichment
  20. 2026-08-24 00:28 UTCGHSA enrichment
  21. 2026-08-23 01:05 UTCEG score recompute
  22. 2026-08-23 01:05 UTCGHSA enrichment
  23. 2026-08-23 00:19 UTCEPSS rescore
  24. 2026-08-21 23:49 UTCEPSS rescore
  25. 2026-08-21 07:31 UTCEG score recompute
Show 75 more
  1. 2026-08-21 07:31 UTCGHSA enrichment
  2. 2026-08-20 22:55 UTCEPSS rescore
  3. 2026-08-20 08:08 UTCEG score recompute
  4. 2026-08-20 08:08 UTCGHSA enrichment
  5. 2026-08-19 17:04 UTCEPSS rescore
  6. 2026-08-19 07:41 UTCEG score recompute
  7. 2026-08-19 07:41 UTCGHSA enrichment
  8. 2026-08-18 13:48 UTCEPSS rescore
  9. 2026-08-17 13:47 UTCEPSS rescore
  10. 2026-08-16 20:40 UTCEG score recompute
  11. 2026-08-16 20:40 UTCGHSA enrichment
  12. 2026-08-16 14:56 UTCEPSS rescore
  13. 2026-08-16 02:14 UTCEPSS rescore
  14. 2026-08-15 21:07 UTCEG score recompute
  15. 2026-08-15 21:07 UTCGHSA enrichment
  16. 2026-08-15 01:30 UTCEPSS rescore
  17. 2026-08-14 21:11 UTCEG score recompute
  18. 2026-08-14 21:11 UTCGHSA enrichment
  19. 2026-08-13 22:00 UTCEPSS rescore
  20. 2026-08-13 21:48 UTCGHSA enrichment
  21. 2026-08-12 21:53 UTCEG score recompute
  22. 2026-08-12 21:53 UTCGHSA enrichment
  23. 2026-08-12 13:51 UTCEPSS rescore
  24. 2026-08-11 22:30 UTCEG score recompute
  25. 2026-08-11 22:30 UTCGHSA enrichment
  26. 2026-08-11 00:00 UTCEPSS rescore
  27. 2026-08-10 23:08 UTCGHSA enrichment
  28. 2026-08-09 23:45 UTCEG score recompute
  29. 2026-08-09 23:45 UTCGHSA enrichment
  30. 2026-08-09 13:46 UTCEPSS rescore
  31. 2026-08-09 00:23 UTCEG score recompute
  32. 2026-08-09 00:23 UTCGHSA enrichment
  33. 2026-08-08 16:37 UTCEPSS rescore
  34. 2026-08-08 01:00 UTCEG score recompute
  35. 2026-08-08 01:00 UTCGHSA enrichment
  36. 2026-08-07 01:38 UTCEG score recompute
  37. 2026-08-07 01:37 UTCGHSA enrichment
  38. 2026-08-06 13:47 UTCEPSS rescore
  39. 2026-08-06 02:15 UTCEG score recompute
  40. 2026-08-06 02:15 UTCGHSA enrichment
  41. 2026-08-05 19:17 UTCEPSS rescore
  42. 2026-08-05 02:53 UTCEG score recompute
  43. 2026-08-05 02:53 UTCGHSA enrichment
  44. 2026-08-04 15:10 UTCEPSS rescore
  45. 2026-08-04 10:39 UTCEPSS rescore
  46. 2026-08-04 03:16 UTCEG score recompute
  47. 2026-08-04 03:16 UTCGHSA enrichment
  48. 2026-08-03 10:36 UTCEPSS rescore
  49. 2026-08-03 03:54 UTCGHSA enrichment
  50. 2026-08-02 04:31 UTCEG score recompute
  51. 2026-08-02 04:31 UTCGHSA enrichment
  52. 2026-08-02 02:27 UTCEPSS rescore
  53. 2026-08-01 05:08 UTCEG score recompute
  54. 2026-08-01 05:08 UTCGHSA enrichment
  55. 2026-08-01 04:16 UTCEPSS rescore
  56. 2026-07-31 03:51 UTCEG score recompute
  57. 2026-07-31 03:51 UTCGHSA enrichment
  58. 2026-07-30 16:28 UTCEPSS rescore
  59. 2026-07-30 03:05 UTCEG score recompute
  60. 2026-07-30 03:05 UTCGHSA enrichment
  61. 2026-07-30 01:30 UTCEPSS rescore
  62. 2026-07-30 01:30 UTCEPSS rescore
  63. 2026-07-29 01:44 UTCEG score recompute
  64. 2026-07-29 01:44 UTCGHSA enrichment
  65. 2026-07-28 15:37 UTCEPSS rescore
  66. 2026-07-27 18:06 UTCEG score recompute
  67. 2026-07-27 18:06 UTCGHSA enrichment
  68. 2026-07-26 17:17 UTCEG score recompute
  69. 2026-07-26 17:17 UTCGHSA enrichment
  70. 2026-07-26 14:54 UTCEPSS rescore
  71. 2026-07-25 14:18 UTCEPSS rescore
  72. 2026-07-24 14:18 UTCEPSS rescore
  73. 2026-07-23 14:18 UTCEPSS rescore
  74. 2026-07-23 03:20 UTCEG score recompute
  75. 2026-07-22 14:08 UTCEPSS rescore

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-56099?
CVE-2026-56099 is a medium vulnerability published on June 18, 2026. OpenBSD before commit 6a23123 (2026-06-18) contains an out-of-bounds read vulnerability in the mplsdoerror function within sys/netmpls/mpls_input.c that allows remote attackers to disclose kernel stack memory by sending crafted MPLS frames with 16 labels and no Bottom-of-Stack bit set.
When was CVE-2026-56099 disclosed?
CVE-2026-56099 was first published in the National Vulnerability Database on June 18, 2026, with the most recent update on July 14, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-56099 actively exploited?
CVE-2026-56099 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 58.7% of all scored CVEs.
What is the CVSS score of CVE-2026-56099?
CVE-2026-56099 has a CVSS v3 base score of 5.3 (NVD).
How do I remediate CVE-2026-56099?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-56099, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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