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CVE-2021-44878

Pac4j token validation bypass if OpenID Connect provider supports none algorithm

7.5 HighFix available

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.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
None
Integrity
High
Availability
None

Exploit likelihood

0.92%Up 0.3 points since Jan 6, 2022
90%50%10%1%

What each source reports

NVD Score used 7.5

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.

Record
CVE-2021-44878
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
CVSS 2.0
5.0 MediumAV:N/AC:L/Au:N/C:N/I:P/A:N
Weakness
CWE-347
Updated
2026-11-02
CVE List No score

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.

Record
CVE-2021-44878
Updated
2026-11-02
EUVDEUVD-2022-0744 No score

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.

Record
EUVD-2022-0744
Updated
2026-11-03
GitHub AdvisoriesGHSA-xhw6-hjc9-679m 7.5

Pac4j token validation bypass if OpenID Connect provider supports none algorithm

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.

Record
GHSA-xhw6-hjc9-679m
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-347
Updated
2026-11-02
OSV 7.5

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.

Record
CVE-2021-44878
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Updated
2026-11-02
OSVGHSA-xhw6-hjc9-679m 7.5

Pac4j token validation bypass if OpenID Connect provider supports none algorithm

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.

Record
GHSA-xhw6-hjc9-679m
CVSS 3.1
7.5 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Weakness
CWE-347
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
org.pac4j:pac4j-oidc
Maven
before 4.5.5
4.5.5
org.pac4j:pac4j-oidc
Maven
5.0 up to 5.3.1
5.3.1
org.pac4j:pac4j-oidc
Maven
before 4.5.5, plus listed versions
1.7.01.7.11.7.21.8.01.8.0-RC1
Show 45 moreShow less
1.8.11.8.21.8.31.8.41.8.51.8.61.8.71.8.81.8.91.9.01.9.11.9.21.9.31.9.41.9.51.9.61.9.71.9.81.9.92.0.02.0.0-RC12.0.0-RC22.1.02.2.02.2.12.3.02.3.13.0.03.0.0-RC13.0.0-RC23.0.13.0.23.1.03.2.03.3.03.4.03.5.03.6.03.6.13.7.03.8.03.8.13.8.23.8.33.9.0
4.5.5
org.pac4j:pac4j-oidc
Maven
5.0 up to 5.3.1, plus listed versions
5.0.05.0.15.1.05.1.15.1.2
Show 6 moreShow less
5.1.35.1.45.1.55.2.05.2.15.3.0
5.3.1

History

History
RecordedChangedSources
aliasesEUVD
first indexedCVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-44878 is a high vulnerability (CVSS 7.5) in Pac4j, published January 6, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.92%, the 60th percentile. Fixed in org.pac4j:pac4j-oidc 4.5.5.

References

This page doesn't list everything

Left out here: 17 versions. The JSON record has them.

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