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TI-2026-71034 Aliases CVE-2026-109399GHSA-xf8v-f779-856c

Improper certificate validation in SWUpdate lets forged updates install

Priority MEDIUM 41CWE-295Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
High
Attack requirements
Present
Impact type
Spoofing
Confidentiality · integrity · availability
High · High · High
Fix status
No fix listed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA. Impact type from CWE-295.

Summary

SWUpdate through 2026.05.1 contains an improper certificate validation flaw in crypto/swupdate_cms_verify_openssl.c. The CMS verification code trusts X.509 certificates embedded in the signature for chain building, which is CWE-295. An attacker holding a signing key from a sibling intermediate under the same root can embed that intermediate in the signature and install malicious updates. The CVSS 4.0 vector shows a network attacker with high attack complexity and no privileges or user interaction.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

SWUpdate through 2026.05.1 contains an improper certificate validation vulnerability in crypto/swupdate_cms_verify_openssl.c that trusts untrusted X.509 certificates embedded in CMS SignedData for chain building. Attackers holding a signing key from a sibling intermediate under the same root can embed that intermediate in the signature to install malicious updates.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00207 10th percentileScored 2026-11-07
Fix No fix listed No fixed version in the sources yet

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Total

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
sbabicswupdateup to 2026.05.1—No fix listedCNA
  • swupdate Vendorsbabic Affected up to 2026.05.1 Fixed in — No fix listed CNA

Remediation

The sources list no fixed version for SWUpdate.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Timeline

  1. 2026-10-12 Threatist record created from CVE-2026-109399
  2. 2026-10-12 Alias added: GHSA-xf8v-f779-856c
  3. 2026-10-13 Priority changed: MEDIUM → LOW
  4. 2026-10-18 CISA SSVC decision points changed
  5. 2026-10-18 Priority changed: LOW → MEDIUM

References

Patch 1

Other 3

  • TI-2025-27505 SWUpdate Untrusted Script Execution via Signed Update TOCTOU CVSS 4.0HIGH 7.3

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences