Skip to main content
VulnerabilityPublished

CVE-2026-42501: Go toolchain cmd/go · Improper Verification of Cryptographic Signature

Affects Go toolchain cmd/goSource CVE Database V5

0
Compare

Not known to be exploited · CVSS 7.5 High : upgrade to 1.26.3 or 1.25.10 soon.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 3.1 base score
7.5High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 1.26.3, 1.25.10
CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 7 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade Go toolchain cmd/go to 1.26.3 or 1.25.10.

Affected software

ProductAffectedFixed in
Go toolchaincmd/goAffected
  • >=1.26.0-0 <1.26.3
Fixed in
  • 1.26.3
Go toolchaincmd/goAffected
  • <1.25.10
Fixed in
  • 1.25.10
Gocmd/gopkg:golang/cmd/goOther threatsAffected
  • <1.25.10
  • >=1.26.0-0 <1.26.3
Fixed in
  • 1.25.10
  • 1.26.3
Gogithub.com/golang/go/cmd/gopkg:golang/github.com/golang/go/cmd/goOther threatsAffected
  • =0
  • =1.26.0-0
Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

In the meantime, users should avoid using untrusted GOPROXY or GOSUMDB configurations. Potential compromise can be detected by regenerating and verifying go.sum files. No other vendor-provided mitigations are currently documented.

Description

CVE-2026-42501 is a high-severity vulnerability in the Go toolchain's cmd/go module handling that allows a malicious module proxy to bypass checksum database validation due to improper verification of cryptographic signatures. This flaw enables acceptance of empty or unrelated checksum responses as valid, potentially leading to execution of altered Go toolchain versions or modules when using untrusted GOPROXY or GOSUMDB configurations. No known exploits have been reported in the wild at this time.

References

Community reviews

Loading reviews…