Vulnerability in Pac4j
CVE-2021-44878
If an OpenID Connect provider supports the "none" algorithm (i.e., tokens with no signature), pac4j v5.3.0 (and prior) does not refuse it without an explicit configuration on its side or for the "idtoken" response type which is not secure and violates the OpenID Core Specification. The "none" algorithm does not require any signature verification when validating the ID tokens, which allows the attacker to bypass the token validation by injecting a malformed ID token using "none" as the value of "alg" key in the header with an empty signature value.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
EPSS exploit prediction
EPSS: 0.009 (57.9th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 58th percentile — 57.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.009 · newest: 0.009 · change: 0.000
Affected products
Weakness classification (CWE)
References
- github.com/pac4j/pac4j/commit/22b82ffd702a132d9f09da60362fc6264fc281ae (Patch, Third Party Advisory)
- openid.net/specs/openid-connect-core-1_0.html (Product, Third Party Advisory)
- www.pac4j.org/blog/cve_2021_44878_is_this_serious.html (Mitigation, Vendor Advisory)
Frequently asked questions
- What is CVE-2021-44878?
- CVE-2021-44878 is a high-severity vulnerability in Pac4j, classified under Improper Verification of Cryptographic Signature. CVSS score: 7.5/10. Published 2022-01-06.
- How severe is CVE-2021-44878?
- High severity. CVSS v3 base score is 7.5 out of 10.