CVE-2026-42501

HIGHNVD 7.57.5
EchelonGraph scoreMEDIUM confidence

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

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-05-07. NVD baseline CVSS 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this week

Also known asEUVD-2026-28433 (ENISA EUVD) · GHSA-qf3q-3h68-mmh2 (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
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: 0.2%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

A malicious module proxy can exploit a flaw in the go command's validation of module checksums to bypass checksum database validation. This vulnerability affects any user using an untrusted module proxy (GOMODPROXY) or checksum database (GOSUMDB). A malicious module proxy can serve altered versions of the Go toolchain. When selecting a different version of the Go toolchain than the currently installed toolchain (due to the GOTOOLCHAIN environment variable, or a go.work or go.mod with a toolchain line), the go command will download and execute a toolchain provided by the module proxy. A malicious module proxy can bypass checksum database validation for this downloaded toolchain. Since this vulnerability affects the security of toolchain downloads, setting GOTOOLCHAIN to a fixed version is not sufficient. You must upgrade your base Go toolchain. The go tool always validates the hash of a toolchain before executing it, so fixed versions will refuse to execute any cached, altered versions of the toolchain. The go tool trusts go.sum files to contain accurate hashes of the current module's dependencies. A malicious proxy exploiting this vulnerability to serve an altered module will have caused an incorrect hash to be recorded in the go.sum. Users who have configured a non-trusted GOPROXY can determine if they have been affected by running "rm go.sum ; go mod tidy ; go mod verify", which will revalidate all dependencies of the current module. The specific flaw in more detail: The go command consults the checksum database to validate downloaded modules, when a module is not listed in the go.sum file. It verifies that the module hash reported by the checksum database matches the hash of the downloaded module. If, however, the checksum database returns a successful response that contains no entry for the module, the go command incorrectly permitted validation to succeed. A module proxy may mirror or proxy the checksum database, in which case the go command will not connect to the checksum database directly. Checksums reported by the checksum database are cryptographically signed, so a malicious proxy cannot alter the reported checksum for a module. However, a proxy which returns an empty checksum response, or a checksum response for an unrelated module, could cause the go command to proceed as if a downloaded module has been validated.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
34
EG Risk 34/100

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)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 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
0.2%
EPSS %ILE
13th
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 (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). 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

May 7, 2026

Last Modified

May 13, 2026

Advisory Details (4)

Auto-updated Jun 6, 2026
Patch available.
Web page

GO-2026-4984 - Go Packages

https://pkg.go.dev/vuln/GO-2026-4984
Web page

cmd/go: malicious module proxy can bypass checksum database (fix CVE-2026-42501) · Issue #79070 · golang/go · GitHub

https://go.dev/issue/79070

Patch Availability(10)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatgolang-0:1.26.5-1.el9_22026-08-31redhat
redhatgolang-0:1.26.5-1.el9_42026-08-20redhat
redhatgolang-0:1.26.5-1.el9_62026-08-03redhat
redhatgolang-0:1.26.5-1.el10_02026-08-03redhat
redhatgolang-fips1-25-main-1.25.9-0.1.1.hum12026-06-29redhat
redhatgolang1-25-main-1.25.11-2.hum12026-06-04redhat
redhatgolang1-26-main-1.26.4-2.hum12026-06-04redhat
redhatgolang-0:1.26.3-1.el9_82026-06-01redhat
redhatgolang-0:1.26.3-4.el10_22026-06-01redhat
redhatgo-toolset:rhel8-8100020260518131104.a3795dee2026-06-01redhat

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

(6 across 5 ecosystems)
Debian:14(2)
PackageVulnerable rangeFix by version rangeDependents
golang-1.251.25.0-1 ... 1.25.9-1 (11 versions)
  • every version up to 1.25.10-1: fixed in 1.25.10-1
—
golang-1.261.26.0-1 ... 1.26~rc3-2 (9 versions)
  • every version up to 1.26.3-1: fixed in 1.26.3-1
—
Debian:11(1)
PackageVulnerable rangeFix by version rangeDependents
golang-1.151.15.15-1 ... 1.15.9-6 (10 versions)
  • every version on: no fix on record
—
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
—
Go(1)
PackageVulnerable rangeFix by version rangeDependents
toolchain—
  • every version up to 1.25.10: fixed in 1.25.10
  • 1.26.0-0 up to 1.26.3: fixed in 1.26.3
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 10× in last 7d / 44× 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 256 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 156 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  2. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  3. 2026-10-30 16:34 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  4. 2026-10-30 05:02 UTCEG score recompute
  5. 2026-10-30 05:02 UTCVendor advisory
  6. 2026-10-30 05:02 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  7. 2026-10-29 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  8. 2026-10-28 16:32 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  9. 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  10. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  11. 2026-10-25 16:33 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  12. 2026-10-25 14:29 UTCEG score recompute
  13. 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  14. 2026-10-23 21:44 UTCEG score recompute
  15. 2026-10-23 21:44 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  16. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  17. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  18. 2026-10-21 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  19. 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  20. 2026-10-19 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  21. 2026-10-18 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  22. 2026-10-18 03:41 UTCEG score recompute
  23. 2026-10-17 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  24. 2026-10-17 14:25 UTCEG score recompute
  25. 2026-10-17 14:25 UTCVendor advisory
Show 75 more
  1. 2026-10-17 14:24 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  2. 2026-10-16 16:42 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  3. 2026-10-15 16:32 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  4. 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  5. 2026-10-13 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  6. 2026-10-12 16:34 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  7. 2026-10-12 16:07 UTCEG score recompute
  8. 2026-10-11 19:49 UTCEG score recompute
  9. 2026-10-11 17:03 UTCEG score recompute
  10. 2026-10-11 14:29 UTCEG score recompute
  11. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  12. 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  13. 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  14. 2026-10-08 17:12 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  15. 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  16. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  17. 2026-10-05 17:43 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  18. 2026-10-04 23:22 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  19. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.3% · 19th percentile
  20. 2026-10-01 19:50 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  21. 2026-09-30 15:03 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  22. 2026-09-30 08:41 UTCOSV refresh
  23. 2026-09-27 13:48 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  24. 2026-09-26 15:58 UTCEPSS rescoreEPSS 0.3% · 18th percentile
  25. 2026-09-23 17:53 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  26. 2026-09-20 20:15 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  27. 2026-09-18 19:28 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  28. 2026-09-17 19:31 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  29. 2026-09-16 14:08 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  30. 2026-09-16 05:15 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  31. 2026-09-13 16:47 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  32. 2026-09-12 15:01 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  33. 2026-09-11 15:23 UTCOSV refresh
  34. 2026-09-11 14:53 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  35. 2026-09-11 09:37 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  36. 2026-09-10 09:34 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  37. 2026-09-08 22:00 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  38. 2026-09-07 16:01 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  39. 2026-09-06 13:47 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  40. 2026-09-04 05:06 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  41. 2026-09-02 14:12 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  42. 2026-09-01 13:54 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  43. 2026-08-30 19:17 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  44. 2026-08-30 01:22 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  45. 2026-08-28 21:41 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  46. 2026-08-27 14:25 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  47. 2026-08-26 14:46 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  48. 2026-08-25 13:49 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  49. 2026-08-23 19:33 UTCEG score recompute
  50. 2026-08-23 19:33 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  51. 2026-08-23 00:19 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  52. 2026-08-21 23:49 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  53. 2026-08-20 22:55 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  54. 2026-08-19 17:03 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  55. 2026-08-18 13:48 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  56. 2026-08-17 13:47 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  57. 2026-08-17 12:43 UTCEG score recompute
  58. 2026-08-17 12:43 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  59. 2026-08-16 14:56 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  60. 2026-08-16 04:42 UTCEG score recompute
  61. 2026-08-16 04:42 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  62. 2026-08-16 02:14 UTCEPSS rescoreEPSS 0.2% · 14th percentile
  63. 2026-08-15 01:30 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  64. 2026-08-14 15:05 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  65. 2026-08-14 03:17 UTCEG score recompute
  66. 2026-08-14 03:17 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  67. 2026-08-13 22:00 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  68. 2026-08-13 04:39 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  69. 2026-08-12 16:52 UTCEG score recompute
  70. 2026-08-12 16:52 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  71. 2026-08-12 13:51 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  72. 2026-08-11 15:55 UTCEG score recompute
  73. 2026-08-11 15:54 UTCGHSA enrichmentGHSA-qf3q-3h68-mmh2 · GitHub severity HIGH · GitHub CVSS 7.5
  74. 2026-08-11 13:43 UTCEPSS rescoreEPSS 0.2% · 13th percentile
  75. 2026-08-11 01:46 UTCEG score recompute

Frequently asked(5)

What is CVE-2026-42501?
CVE-2026-42501 is a high-severity vulnerability; its CVE record was published on May 7, 2026. A malicious module proxy can exploit a flaw in the go command's validation of module checksums to bypass checksum database validation. This vulnerability affects any user using an untrusted module proxy (GOMODPROXY) or checksum database (GOSUMDB). A malicious module proxy can serve altered versions…
When was the CVE record for CVE-2026-42501 published?
The CVE record for CVE-2026-42501 was published on May 7, 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 May 13, 2026; the record at its source may have been updated since.
Is CVE-2026-42501 actively exploited?
CVE-2026-42501 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (13th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-42501?
CVE-2026-42501 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-42501?
A fix for CVE-2026-42501 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-42501 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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