CVE-2026-56786

CRITICALPre-NVD 9.89.8
EchelonGraph scoreMEDIUM confidence

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

Score 9.8 from GitHub Security Advisory (severity: CRITICAL) published 2026-06-25. A secondary CVSS source baseline 9.8; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 3 sources updated this weekElevated

Also known asEUVD-2026-39528 (ENISA EUVD) · GHSA-5cx9-6hw2-hchv (GitHub Security Advisories)Source: ENISA EUVD

9.8EG
EchelonGraph verdictPlan mitigationRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 9.8Exploit: No code on recordExposed services: Not assessed

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

The CVE record's CNA (VulnCheck) lists tomojitakasu RTKLIB versions up to and including 2.4.3 as affected. No release containing a fix is confirmed on record.

RTKLIB through 2.4.3 contains an out-of-bounds write vulnerability in decode_type1033 function that fails to clamp length counters to destination buffer size, allowing up to 191-byte overflow into fixed 64-byte descriptor fields. An attacker controlling an NTRIP or serial RTCM3 correction stream can craft a valid CRC-bearing type-1033 message to corrupt adjacent rtcm_t object members, potentially achieving arbitrary code execution or denial of service.

CVSS v3
9.8
EG Score
9.8CRITICALmedium confidence
EG Risk
75
EG Risk 75/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity98% × 45%
Impact severity (EG Severity): CVSS 9.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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: No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.
EPSS PROB
0.7%
EPSS %ILE
53rd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (9.8): severity, escalated by confirmed exploitation. This CVE's 9.8 is its impact severity (EG Severity), not escalated.

EG Severity
9.8 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.7% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-26). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track* at medium mission impactTrack at low, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 3 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low, Track* at medium and Attend at high mission impact.

No fix is confirmed yet. Restrict network exposure of the affected system or apply the vendor's mitigation within your standard update timelines at low or medium mission impact and sooner than that at high, and watch the vendor's advisory for the fix.

Exploitation public PoC (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact total (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)3 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact total (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

June 25, 2026

Last Modified

October 25, 2026

Advisory Details (2)

Auto-updated Oct 26, 2026
🔬 Proof of concept available. No fix on record yet.
Web page

RTKLIB 2.4.3 - Out-of-bounds Write in decode_type1033 via Crafted RTCM3 Message | Advisories | VulnCheck

https://www.vulncheck.com/advisories/rtklib-out-of-bounds-write-in-decode-type1033-via-crafted-rtcm3-message
Web page🟡 PoC Available

Out-of-Bounds Write in RTKLIB decode_type1033 via Unbounded RTCM3 Antenna/Receiver Descriptor Lengths · Issue #799 · tomojitakasu/RTKLIB · GitHub

https://github.com/tomojitakasu/RTKLIB/issues/799

Vendor Advisories for CVE-2026-56786(1)

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

Affected Packages

(4 across 4 ecosystems)
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
rtklib2.4.3+dfsg1-2.1 ... 2.4.3.b34+dfsg-1 (8 versions)
  • every version on: no fix on record
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
rtklib2.4.3.b34+dfsg-1
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
rtklib2.4.3.b34+dfsg-1
  • every version on: no fix on record
—
Debian:14(1)
PackageVulnerable rangeFix by version rangeDependents
rtklib2.4.3.b34+dfsg-1
  • every version on: no fix on record
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 21× in last 7d / 65× 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.

Showing the most recent 100 of 498 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 398 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  2. 2026-10-27 12:59 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-10-27 04:57 UTCEG score recompute
  4. 2026-10-27 04:57 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  6. 2026-10-25 22:26 UTCEG score recompute
  7. 2026-10-25 22:26 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  8. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  9. 2026-10-25 14:17 UTCEG score recompute
  10. 2026-10-25 03:52 UTCEG score recompute
  11. 2026-10-25 03:52 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  13. 2026-10-24 01:29 UTCEG score recompute
  14. 2026-10-24 01:29 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  15. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  16. 2026-10-22 23:06 UTCEG score recompute
  17. 2026-10-22 23:06 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  19. 2026-10-21 20:42 UTCEG score recompute
  20. 2026-10-21 20:42 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  22. 2026-10-20 18:17 UTCEG score recompute
  23. 2026-10-20 18:17 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  25. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
Show 75 more
  1. 2026-10-19 15:53 UTCEG score recompute
  2. 2026-10-19 15:53 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  3. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  4. 2026-10-18 13:29 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  5. 2026-10-18 03:29 UTCEG score recompute
  6. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  7. 2026-10-17 11:06 UTCEG score recompute
  8. 2026-10-17 11:06 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  9. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  10. 2026-10-16 08:41 UTCEG score recompute
  11. 2026-10-16 08:41 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  12. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  13. 2026-10-15 06:16 UTCEG score recompute
  14. 2026-10-15 06:15 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  15. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  16. 2026-10-14 01:54 UTCEG score recompute
  17. 2026-10-14 01:54 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  18. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  19. 2026-10-12 22:11 UTCEG score recompute
  20. 2026-10-12 22:10 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  21. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  22. 2026-10-12 15:54 UTCEG score recompute
  23. 2026-10-12 06:48 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  24. 2026-10-11 19:38 UTCEG score recompute
  25. 2026-10-11 16:53 UTCEG score recompute
  26. 2026-10-11 14:15 UTCEG score recompute
  27. 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  28. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  29. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  30. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  31. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  32. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  33. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  34. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  35. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  36. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  37. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  38. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  39. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  40. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  41. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  42. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  43. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  44. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  45. 2026-09-23 08:29 UTCEG score recompute
  46. 2026-09-23 08:29 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  47. 2026-09-20 20:16 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  48. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.7% · 52nd percentile
  49. 2026-09-18 11:16 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  50. 2026-09-18 07:20 UTCEG score recompute
  51. 2026-09-18 07:20 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  52. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  53. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  54. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  55. 2026-09-15 03:11 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  56. 2026-09-14 09:09 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  57. 2026-09-14 05:13 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  58. 2026-09-14 01:17 UTCEG score recompute
  59. 2026-09-14 01:17 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  60. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  61. 2026-09-13 13:45 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  62. 2026-09-13 09:37 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  63. 2026-09-12 15:43 UTCEG score recompute
  64. 2026-09-12 15:43 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  65. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  66. 2026-09-10 09:35 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  67. 2026-09-08 22:01 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  68. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  69. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  70. 2026-09-04 05:07 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  71. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  72. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  73. 2026-09-01 04:40 UTCEPSS rescoreEPSS 0.7% · 51st percentile
  74. 2026-08-30 23:30 UTCGHSA enrichmentGHSA-5cx9-6hw2-hchv · GitHub severity CRITICAL · GitHub CVSS 9.8
  75. 2026-08-30 19:31 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-56786?
CVE-2026-56786 is a critical-severity vulnerability; its CVE record was published on June 25, 2026. RTKLIB through 2.4.3 contains an out-of-bounds write vulnerability in decodetype1033 function that fails to clamp length counters to destination buffer size, allowing up to 191-byte overflow into fixed 64-byte descriptor fields. An attacker controlling an NTRIP or serial RTCM3 correction stream can…
When was CVE-2026-56786 made public?
CVE-2026-56786 was made public on June 9, 2026: that is the date its CVE record's CNA, VulnCheck, gives for when the vulnerability was made public. The CVE record itself was published on June 25, 2026. EchelonGraph's copy of the record carries a last-modified date of October 25, 2026; the record at its source may have been updated since.
Is CVE-2026-56786 actively exploited?
CVE-2026-56786 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (53rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-56786?
CVE-2026-56786 has a CVSS base score of 9.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-56786?
No fix for CVE-2026-56786 is confirmed yet. Until one is published, restrict network exposure of the affected system or apply the vendor's mitigation — for example, keep it off the internet or limit it to trusted networks — and watch the vendor's advisory for the fix. The CVE record's CNA (VulnCheck) lists tomojitakasu RTKLIB versions up to and including 2.4.3 as affected. No release containing a fix is confirmed on record. The vendor advisories EchelonGraph has for CVE-2026-56786 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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