GoAhead TLS flaws can ignore CRLs, weaken encryption, or bypass chain limits
Original title: TLS Flaws Found in GoAhead Web Server Used in Hundreds of Millions of Devices
FoxIO published PoCs for three configuration-specific bugs; GoAhead 6.1.1 fixes the OpenSSL and Mbed TLS issues.
FoxIO disclosed three flaws in EmbedThis GoAhead’s TLS handling that can accept revoked client certificates, let some recorded TLS 1.2 sessions be decrypted offline, or bypass a certificate-chain length cap. Each bug hits only certain library and configuration combinations on the embedded web server, which FoxIO says is on hundreds of millions of IoT, OT, firewall and military devices. GoAhead 6.1.1, released August 2, fixes the OpenSSL and Mbed TLS issues; advisories appeared October 12. FoxIO released proof-of-concept code and fingerprints but did not say named vendors’ products use a vulnerable setup.
Unconfirmed: FoxIO has not confirmed that products from the named device makers use a vulnerable configuration; the decryption bug has no CVE.
- CVE-2026-115881 (CVSS 9.1) affects GoAhead 3.4.5 through 6.1.0 with OpenSSL and mTLS CRLs.
- The server loads the CRL but never asks OpenSSL to consult it, so revoked certificates are accepted.
- An unnamed CVSS 5.9 bug hits GoAhead 4.0.2 through 6.1.0 builds using Mbed TLS.
- CVE-2026-115884 (CVSS 7.4) affects builds up to 6.1.0 using specified LibreSSL versions.
- 6.1.1 does not, as stated, fix the LibreSSL chain-length issue.
Impact: Revoked client certs accepted, or some TLS 1.2 traffic decryptable offline
| Product | Affected | Fixed in |
|---|---|---|
| EmbedThis GoAhead | 3.4.5 through 6.1.0 with OpenSSL or a compatible library, mTLS and a CRL | 6.1.1 |
| EmbedThis GoAhead | 4.0.2 through 6.1.0 using Mbed TLS | 6.1.1 |
| EmbedThis GoAhead | up to 6.1.0 built with LibreSSL 3.2.x or 3.3.2 through 3.3.6 | — |
- 1.Upgrade affected OpenSSL and Mbed TLS builds to GoAhead 6.1.1.
- 2.Disable finite-field DHE cipher suites or switch Mbed TLS builds to the OpenSSL backend.
- 3.Enable issuer verification with a trusted CA, or use OpenSSL or LibreSSL 4.x.
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2026-115881 | — | — | — | ||
| CVE-2026-115884 | — | — | — |
From the original article
2 min read at securityweek.com
FoxIO disclosed three GoAhead TLS bugs that can let revoked certificates through or expose some encrypted sessions to eavesdroppers. The post TLS Flaws Found in GoAhead Web Server Used in Hundreds of Millions of Devices appeared first on SecurityWeek.
By Eduard Kovacs · securityweek.com
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