cve.bz

CVE-2021-44878

7.5 highEPSS 0.9%

High (7.5) in pac4j pac4j. EPSS 0.9% chance of exploitation in the next 30 days. Fixed in org.pac4j:pac4j-oidc 4.5.5, 5.3.1.

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.

Severity

CVSS 3.1

7.5 high
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
EPSS
0.9% chance of exploitation in the next 30 days; higher than 60% of CVEs (scores of 2026-10-31)
CWE
CWE-347
Published
Modified
Record from
the NVD, synced

Affected

Packages (OSV)

AdvisoryEcosystemPackageAffectedFixed in
GHSA-xhw6-hjc9-679mMavenorg.pac4j:pac4j-oidc<4.5.54.5.5
GHSA-xhw6-hjc9-679mMavenorg.pac4j:pac4j-oidc>=5.0 <5.3.15.3.1

References

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