Vulnpedia
← Search CVEs

CVE-2026-105221

CRITICAL 9.1

Published 2026-10-04 · Last modified 2026-10-05

The gist RubyGem before 6.1.0 contains an improper certificate validation vulnerability that allows on-path attackers to intercept HTTPS traffic because http_connection in lib/gist.rb sets VERIFY_NONE. Attackers can present any certificate to read or modify GitHub API traffic, stealing OAuth tokens and login credentials to read and modify the victim's gists.

ELEVATED IMPACT

Severe if exploited (CVSS 9.1), but no known exploitation and low modeled probability. Patch on a normal cadence.

Exploitation likelihood

0.2%chance of exploitation in 30 days · 13th percentile

○ In CISA KEV ○ Catalogued PoC

Impact if exploited

9.1CVSS 4.0 · CRITICAL

  • ConfidentialityHigh
  • IntegrityHigh
  • AvailabilityNone

What an attacker needs

  • ✓Access: Reachable over the network — no local access needed
  • ✓Privileges: No account or privileges required
  • ✓User interaction: No user interaction needed
  • ⚠Complexity: Needs a race window or specific setup
  • ⚠Requirements: Specific conditions must be present

✓ lowers the bar for an attacker · ⚠ raises it

Proof of concept

No public PoC is currently catalogued.

Search for new PoCs

Search GitHub now — results may be empty or unverified.

Tracked sources are checked daily for recent CVEs, including PoCs published after the original disclosure. A later release appears after a tracked source lists it and a refresh succeeds.

Data snapshot:

Affected

Vendors Defunkt

Products Gist

Weakness (CWE)

  • CWE-295: Improper Certificate Validation

CVSS vector

CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N

References and research data (JSON)

Vendor product assessments

  • All currently supported Red Hat products · known not affected

    Vendor assessment for this product only.

    Reason: vulnerable code not present

    Red Hat · CVE-2026-105221 · Updated 2026-10-06T05:35:07+00:00

Unverified PoC candidates

Catalogue matches for further research. These repositories have not been validated as working exploits.

1 candidate

All CVSS metrics

  • CRITICAL 9.1 v4.0 · CNA Primary
    CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
  • HIGH 7.4 v3.1 · CNA Primary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
  • CRITICAL 9.1 v4.0 · NVD Secondary
    CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
  • HIGH 7.4 v3.1 · NVD Secondary
    CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

References

Patches & mitigations

Advisories

Technical & other

Sources: NVD · CVE.org · EPSS