Description
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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| sbabic | swupdate | ≤ 2026.05.1 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | swupdate | 2026.05+dfsg-1 | — |
| Debian 12 | swupdate | 2022.12+dfsg-4+deb12u3 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | swupdate | No fix yet | — |
| Ubuntu 26.04 LTS | swupdate | No fix yet | — |
| Ubuntu 24.04 LTS | swupdate | No fix yet | — |
| Ubuntu 22.04 LTS | swupdate | No fix yet | — |
References
- Researcher Disclosure technical-description mailing-list
- https://github.com/sbabic/swupdate/commit/e66c5640664a31668926a24c0c84b6b6570dc0d9 patch
- https://github.com/sbabic/swupdate/blob/2026.05.1/crypto/swupdate_cms_verify_openssl.c technical-description
- https://github.com/sbabic/swupdate product
- VulnCheck Advisory: SWUpdate through 2026.05.1 CMS Signature Verification Bypass via Embedded Intermediates third-party-advisory