CVE-2026-56865

highpriority · track · 0EPSS 0.001 · 3 %ileDEEUFRUS
grimoire priorityP2 · Scheduled
Exploitable?
—
no known exploitation
Likely / severe?
0.13% (3rd) EPSS
CVSS 8.4 · high
Is it mine?
25 products
Check your exposure
Who says so?
5 sources
cnnvd · enisa_euvd · osv · cert_bund

EPSS · scored 2026-10-27

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

01

cvss

Technical severity, 0–10. One row per scoring source.

8.4
010

base score 0–10 · higher = more severe · hover a vector to decode

v3.18.4highCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondary · ENISA EU
v3.18.4highCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:Hsecondaryexploitability 2.5 · impact 5.9
v3.17.7highCVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)
02

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS
03

weaknesses

The CWE weakness classes this flaw belongs to.

04

affected products (25)

Products and version ranges known to be affected.

showing 20 of 25
05

advisories (4)

Vendor and ecosystem advisories describing this.

  • WID-SEC-W-2026-2850Golang Go: Mehrere SchwachstellenDeutsch2026-08-13csaf · cert_bundDE

    Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in Golang Go ausnutzen, um einen Denial of Service zu verursachen, ein Cross Site Scripting durchzuführen, Sicherheitsmaßnahmen zu umgehen oder Daten zu manipulieren.

  • BIT-golang-2026-56865Fix transparency log tile verification bypass in golang.org/x/mod/sumdb/tlog2026-08-19vendor · osvUS

    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

  • CERTFR-2026-AVI-1385Multiples vulnérabilités dans les produits VMwareFrançais2026-10-26vendor · certfrFR
  • GO-2026-6179Fix transparency log tile verification bypass in golang.org/x/mod/sumdb/tlog2026-08-13vendor · osvUS

    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

06

also known as (4)

Other names and identifiers for this entity.

07

sources

Which sources assert this record, and when.

published 2026-08-13modified 2026-09-03
08

references (15)

External citations — patches, advisories, analysis.

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