CVE-2024-47832: SSOReady has an XML Signature Bypass via differential XML parsing

Should you act?

Critical and remotely reachable

No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.

• No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
• EPSS 0.4%, percentile 33: FIRST’s model estimates a 0.4% chance of exploitation activity in the next 30 days, higher than 33% of all scored CVEs (low). EPSS is a probability, not a verdict.
• Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
• Only applies if your dependency tree includes github.com/ssoready/ssoready (Go) < 0.0.0-20241009153838-7f92a0630439, fixed in 0.0.0-20241009153838-7f92a0630439. Check your lockfile, including transitive dependencies.

What it is

ssoready is a single sign on provider implemented via docker. Affected versions are vulnerable to XML signature bypass attacks. An attacker can carry out signature bypass if you have access to certain IDP-signed messages. The underlying mechanism exploits differential behavior between XML parsers. Users of https://ssoready.com, the public hosted instance of SSOReady, are unaffected. We advise folks who self-host SSOReady to upgrade to 7f92a06 or later. Do so by updating your SSOReady Docker images from sha-... to sha-7f92a06. There are no known workarounds for this vulnerability.

From the GitHub advisory

Affected versions are vulnerable to XML signature bypass attacks. An attacker can carry out signature bypass if you have access to certain IDP-signed messages. The underlying mechanism exploits differential behavior between XML parsers.

Users of https://ssoready.com, the public hosted instance of SSOReady, are unaffected. We advise folks who self-host SSOReady to upgrade to 7f92a06 or later. Do so by updating your SSOReady Docker images from sha-... to sha-7f92a06. The documentation for self-hosting SSOReady is available here.

Vulnerability was discovered by @ahacker1-securesaml. It's likely the precise mechanism of attack affects other SAML implementations, so the reporter and I (@ucarion) have agreed to not disclose it in detail publicly at this time.

Weakness type: CWE-347.

Product: github.com/ssoready/ssoready (Go) · Assigned by: GitHub_M · Published: 2024-10-09

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: none (no login)
• User interaction: none

CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.

Exploitation and urgency

• CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
• CISA SSVC assessment: exploitation none, automatable yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.40% probability of exploitation activity in the next 30 days; percentile 33.

Timeline

• 2024-10-09 — CVE record published by GitHub_M
• 2024-10-11 — CVE record last updated
• 2024-10-11 — GitHub-reviewed advisory GHSA-j2hr-q93x-gxvh published (critical)

Sources and references

Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.

Vulnerability records

1. GitHub Advisory GHSA-j2hr-q93x-gxvh github.com
2. CVE.org record CVE-2024-47832 cve.org
3. NVD entry CVE-2024-47832 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com
2. github.com github.com
3. ssoready.com ssoready.com
4. pkg.go.dev pkg.go.dev

Critical Go advisories · Today’s Security Digest