CVE-2026-56865

HIGHPre-NVD 8.48.4
EchelonGraph scoreMEDIUM confidence

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

This high-severity CVE scores 8.4 under CISA-ADP (Vulnrichment) CVSS v3.1 (NVD's own analysis pending). EPSS exploit probability: 0.1% (2nd percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from CISA-ADP (Vulnrichment) CVSS v3.1
Sources: CISA-ADP (Vulnrichment) CVSS v3.1, EPSS

Also known asEUVD-2026-58513 (ENISA EUVD) · GO-2026-6179 (OSV.dev)Source: ENISA EUVD

8.4EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.1%CVSS: 8.4Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache. This attack allows for a malicious GOPROXY to serve malicious module content that cannot be detected by evaluating the transparency log. All tiles are now correctly verified against their parents. In order to determine if you have been affected: rm -r go.sum go.work.sum vendor/ && go mod tidy

CVSS v3
8.4
EG Score
8.4HIGHmedium confidence
EG Risk
38
EG Risk 38/100

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)
Severity84% × 45%
Impact severity (EG Severity): CVSS 8.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.1% × 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 low or medium mission impact; Track* at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable no (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: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.1%
EPSS %ILE
2nd
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 (8.4): severity, escalated by confirmed exploitation. This CVE's 8.4 is its impact severity (EG Severity), not escalated.

EG Severity
8.4 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.CISA-ADP (Vulnrichment) CVSS v3.1 · CVSS v3.1
EG Likelihood
0.1% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-08). 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 or medium mission impact; Track* at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Track* at high (mission-essential systems).

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

Exploitation none (CISA Vulnrichment) · Automatable no (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)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (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

August 13, 2026

Last Modified

September 3, 2026

Advisory Details (5)

Auto-updated Aug 14, 2026
Patch available.
Web page

GO-2026-6179 - Go Packages

https://pkg.go.dev/vuln/GO-2026-6179
Web page
https://go.dev/cl/815020
Web page
https://go.dev/cl/814960
Web page
https://groups.google.com/g/golang-announce/c/94pEornpRlI
Web page

x/mod/sumdb/tlog: fix transparency log tile verification bypass · Issue #80744 · golang/go · GitHub

https://go.dev/issue/80744

Vendor Advisories for CVE-2026-56865(3)

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

Patch Availability(3)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntugolang-1.22-src (1.22.2-2ubuntu0.5) @ noble2026-11-01ubuntu
redhatcluster-observability-operator/cluster-observability-rhel9-operator:17908545992026-10-01redhat
redhatadvanced-cluster-security/rhacs-rhel9-operator:17894113202026-09-15redhat

Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.

Affected Packages

(8 across 5 ecosystems)
Debian:14(3)
PackageVulnerable rangeFix by version rangeDependents
golang-1.251.25.0-1 ... 1.25.9-1 (20 versions)
  • every version on: no fix on record
—
golang-1.261.26.0-1 ... 1.26~rc3-2 (16 versions)
  • every version up to 1.26.6-1: fixed in 1.26.6-1
—
golang-1.271.27~rc1-1, 1.27~rc2-1
  • every version up to 1.27~rc3-1: fixed in 1.27~rc3-1
—
Go(2)
PackageVulnerable rangeFix by version rangeDependents
golang.org/x/mod—
  • every version up to 0.40.0: fixed in 0.40.0
—
toolchain—
  • every version up to 1.25.13: fixed in 1.25.13
  • 1.26.0-0 up to 1.26.6: fixed in 1.26.6
  • 1.27.0-0 up to 1.27.0-rc.3: fixed in 1.27.0-rc.3
—
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
go—
  • every version up to 1.26.8-r0: fixed in 1.26.8-r0
—
Debian:12(1)
PackageVulnerable rangeFix by version rangeDependents
golang-1.191.19.10-1 ... 1.19.9-1 (12 versions)
  • every version on: no fix on record
—
Debian:13(1)
PackageVulnerable rangeFix by version rangeDependents
golang-1.241.24.12-1 ... 1.24.9-1 (10 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 7× in last 7d / 32× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 180 rows 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 80 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:53 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  2. 2026-11-12 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  3. 2026-11-11 16:40 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  4. 2026-11-10 16:44 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  5. 2026-11-08 18:57 UTCEchelonGraph re-scored
  6. 2026-11-08 18:57 UTCVendor advisory
  7. 2026-11-08 16:40 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  8. 2026-11-07 16:39 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  9. 2026-11-06 16:38 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  10. 2026-11-05 16:38 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  11. 2026-11-04 16:36 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  12. 2026-11-03 16:48 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  13. 2026-11-02 16:45 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  14. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  15. 2026-11-01 05:38 UTCEchelonGraph re-scored
  16. 2026-11-01 05:38 UTCVendor advisory
  17. 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  18. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  19. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  20. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  21. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  22. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  23. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  24. 2026-10-25 14:17 UTCEchelonGraph re-scored
  25. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
Show 75 more
  1. 2026-10-24 16:19 UTCEchelonGraph re-scored
  2. 2026-10-24 16:19 UTCVendor advisory
  3. 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  4. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  5. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  6. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  7. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  8. 2026-10-18 03:29 UTCEchelonGraph re-scored
  9. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  10. 2026-10-17 02:42 UTCEchelonGraph re-scored
  11. 2026-10-17 02:42 UTCVendor advisory
  12. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  13. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  14. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  15. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  16. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  17. 2026-10-12 15:54 UTCEchelonGraph re-scored
  18. 2026-10-11 19:37 UTCEchelonGraph re-scored
  19. 2026-10-11 16:53 UTCEchelonGraph re-scored
  20. 2026-10-11 14:15 UTCEchelonGraph re-scored
  21. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  22. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  23. 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  24. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  25. 2026-10-06 22:57 UTCEchelonGraph re-scored
  26. 2026-10-06 22:57 UTCVendor advisory
  27. 2026-10-06 15:18 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  28. 2026-10-06 09:25 UTCEchelonGraph re-scored
  29. 2026-10-06 09:25 UTCVendor advisory
  30. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  31. 2026-10-05 14:34 UTCEchelonGraph re-scored
  32. 2026-10-05 14:34 UTCVendor advisory
  33. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  34. 2026-10-04 22:14 UTCVendor advisory
  35. 2026-10-04 08:11 UTCVendor advisory
  36. 2026-10-03 19:43 UTCEchelonGraph re-scored
  37. 2026-10-03 19:43 UTCVendor advisory
  38. 2026-10-03 14:26 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  39. 2026-10-02 19:39 UTCEchelonGraph re-scored
  40. 2026-10-02 19:39 UTCVendor advisory
  41. 2026-10-02 17:56 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  42. 2026-10-02 07:24 UTCEchelonGraph re-scored
  43. 2026-10-02 07:24 UTCVendor advisory
  44. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  45. 2026-10-01 09:58 UTCVendor advisory
  46. 2026-09-30 21:43 UTCEchelonGraph re-scored
  47. 2026-09-30 21:43 UTCVendor advisory
  48. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  49. 2026-09-29 15:22 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  50. 2026-09-29 03:24 UTCEchelonGraph re-scored
  51. 2026-09-29 03:24 UTCVendor advisory
  52. 2026-09-28 13:51 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  53. 2026-09-28 12:48 UTCVendor advisory
  54. 2026-09-28 00:32 UTCEchelonGraph re-scored
  55. 2026-09-28 00:32 UTCVendor advisory
  56. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  57. 2026-09-27 09:40 UTCEchelonGraph re-scored
  58. 2026-09-27 09:40 UTCVendor advisory
  59. 2026-09-26 15:59 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  60. 2026-09-25 03:25 UTCEchelonGraph re-scored
  61. 2026-09-25 03:25 UTCVendor advisory
  62. 2026-09-24 14:04 UTCEPSS rescoreEPSS 0.1% · 2nd percentile
  63. 2026-09-24 09:43 UTCVendor advisory
  64. 2026-09-23 21:27 UTCEchelonGraph re-scored
  65. 2026-09-23 21:27 UTCVendor advisory
  66. 2026-09-23 17:54 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  67. 2026-09-23 09:12 UTCVendor advisory
  68. 2026-09-22 20:57 UTCEchelonGraph re-scored
  69. 2026-09-22 20:57 UTCVendor advisory
  70. 2026-09-22 04:48 UTCEchelonGraph re-scored
  71. 2026-09-22 04:48 UTCVendor advisory
  72. 2026-09-21 16:21 UTCVendor advisory
  73. 2026-09-21 03:57 UTCVendor advisory
  74. 2026-09-20 15:41 UTCVendor advisory
  75. 2026-09-20 01:36 UTCEchelonGraph re-scored

Related CVEs(same product + same vendor + same CWE)

Frequently asked(5)

What is CVE-2026-56865?
CVE-2026-56865 is a high-severity vulnerability; its CVE record was published on August 13, 2026. A malicious GOPROXY was previously capable of forging up to two sumdb tiles that allow for a requested module to bypass the GOSUMDB check and persist attacker-controlled module content to a local Go module cache. This attack allows for a malicious GOPROXY to serve malicious module content that…
When was the CVE record for CVE-2026-56865 published?
The CVE record for CVE-2026-56865 was published on August 13, 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 3, 2026; the record at its source may have been updated since.
Is CVE-2026-56865 actively exploited?
CVE-2026-56865 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.1% probability of exploitation in the next 30 days (2nd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-56865?
CVE-2026-56865 has a CVSS v3.1 base score of 8.4 (CISA-ADP / Vulnrichment enrichment; NVD's own analysis pending).
How do I remediate CVE-2026-56865?
A fix for CVE-2026-56865 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-56865 are linked in the Vendor Advisories panel on this page.

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