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CVE-2022-25898

Improper Verification of Cryptographic Signature

7.7 HighFix available

The package jsrsasign before 10.5.25 are vulnerable to Improper Verification of Cryptographic Signature when JWS or JWT signature with non Base64URL encoding special characters or number escaped characters may be validated as valid by mistake. Workaround: Validate JWS or JWT signature if it has Base64URL and dot safe string before executing JWS.verify() or JWS.verifyJWT() method.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
High
Privileges needed
Low
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
Low
Availability
High

Exploit likelihood

1.15%Up 0.1 points since Jul 2, 2022
90%50%10%1%

What each source reports

CVE List Score used 7.7

Improper Verification of Cryptographic Signature

The package jsrsasign before 10.5.25 are vulnerable to Improper Verification of Cryptographic Signature when JWS or JWT signature with non Base64URL encoding special characters or number escaped characters may be validated as valid by mistake. Workaround: Validate JWS or JWT signature if it has Base64URL and dot safe string before executing JWS.verify() or JWS.verifyJWT() method.

Record
CVE-2022-25898
CVSS 3.1
7.7 HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:H/E:P
Updated
2026-11-02
EUVDEUVD-2022-5902 7.7

The package jsrsasign before 10.5.25 are vulnerable to Improper Verification of Cryptographic Signature when JWS or JWT signature with non Base64URL encoding special characters or number escaped characters may be validated as valid by mistake. Workaround: Validate JWS or JWT signature if it has Base64URL and dot safe string before executing JWS.verify() or JWS.verifyJWT() method.

Record
EUVD-2022-5902
CVSS 3.1
7.7 HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:H/E:P
Updated
2026-11-03
GitHub AdvisoriesGHSA-3fvg-4v2m-98jf 8.6

JWS and JWT signature validation vulnerability with special characters

Impact

Jsrsasign supports JWS(JSON Web Signatures) and JWT(JSON Web Token) validation. However JWS or JWT signature with non Base64URL encoding special characters or number escaped characters may be validated as valid by mistake.

For example, even if a string of non Base64URL encoding characters such as !@$% or \11 is inserted into a valid JWS or JWT signature value string, it will still be a valid JWS or JWT signature by mistake.

When jsrsasign's JWS or JWT validation is used in OpenID connect or OAuth2, this vulnerability will affect to authentication or authorization.

By our internal assessment, CVSS 3.1 score will be 8.6. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Patches

Users validate JWS or JWT signatures should upgrade to 10.5.25.

Workarounds

Validate JWS or JWT signature if it has Base64URL and dot safe string before executing JWS.verify() or JWS.verifyJWT() method.

ACKNOWLEDGEMENT

Thanks to Adi Malyanker and Or David for this vulnerability report. Also thanks for Snyk security team for this coordination.

References

https://github.com/kjur/jsrsasign/releases/tag/10.5.25 https://github.com/kjur/jsrsasign/security/advisories/GHSA-3fvg-4v2m-98jf kjur's advisories https://github.com/advisories/GHSA-3fvg-4v2m-98jf github advisories https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-25898 https://kjur.github.io/jsrsasign/api/symbols/KJUR.jws.JWS.html#.verifyJWT https://kjur.github.io/jsrsasign/api/symbols/KJUR.jws.JWS.html#.verify https://kjur.github.io/jsrsasign/api/symbols/global__.html#.isBase64URLDot https://github.com/kjur/jsrsasign/wiki/Tutorial-for-JWS-verification https://github.com/kjur/jsrsasign/wiki/Tutorial-for-JWT-verification https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-2869122

Record
GHSA-3fvg-4v2m-98jf
CVSS 3.1
8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
Weakness
CWE-347
Updated
2026-11-02
NVD 7.7

The package jsrsasign before 10.5.25 are vulnerable to Improper Verification of Cryptographic Signature when JWS or JWT signature with non Base64URL encoding special characters or number escaped characters may be validated as valid by mistake. Workaround: Validate JWS or JWT signature if it has Base64URL and dot safe string before executing JWS.verify() or JWS.verifyJWT() method.

Record
CVE-2022-25898
CVSS 3.1
7.7 HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:H
CVSS 3.1
9.8 CriticalCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CVSS 2.0
7.5 HighAV:N/AC:L/Au:N/C:P/I:P/A:P
Weakness
CWE-347
Updated
2026-11-02
OSV 7.7

Improper Verification of Cryptographic Signature

The package jsrsasign before 10.5.25 are vulnerable to Improper Verification of Cryptographic Signature when JWS or JWT signature with non Base64URL encoding special characters or number escaped characters may be validated as valid by mistake. Workaround: Validate JWS or JWT signature if it has Base64URL and dot safe string before executing JWS.verify() or JWS.verifyJWT() method.

Record
CVE-2022-25898
CVSS 3.1
7.7 HighCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:H/E:P
Updated
2026-11-02
OSVGHSA-3fvg-4v2m-98jf 8.6

JWS and JWT signature validation vulnerability with special characters

Impact

Jsrsasign supports JWS(JSON Web Signatures) and JWT(JSON Web Token) validation. However JWS or JWT signature with non Base64URL encoding special characters or number escaped characters may be validated as valid by mistake.

For example, even if a string of non Base64URL encoding characters such as !@$% or \11 is inserted into a valid JWS or JWT signature value string, it will still be a valid JWS or JWT signature by mistake.

When jsrsasign's JWS or JWT validation is used in OpenID connect or OAuth2, this vulnerability will affect to authentication or authorization.

By our internal assessment, CVSS 3.1 score will be 8.6. CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N

Patches

Users validate JWS or JWT signatures should upgrade to 10.5.25.

Workarounds

Validate JWS or JWT signature if it has Base64URL and dot safe string before executing JWS.verify() or JWS.verifyJWT() method.

ACKNOWLEDGEMENT

Thanks to Adi Malyanker and Or David for this vulnerability report. Also thanks for Snyk security team for this coordination.

References

https://github.com/kjur/jsrsasign/releases/tag/10.5.25 https://github.com/kjur/jsrsasign/security/advisories/GHSA-3fvg-4v2m-98jf kjur's advisories https://github.com/advisories/GHSA-3fvg-4v2m-98jf github advisories https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2022-25898 https://kjur.github.io/jsrsasign/api/symbols/KJUR.jws.JWS.html#.verifyJWT https://kjur.github.io/jsrsasign/api/symbols/KJUR.jws.JWS.html#.verify https://kjur.github.io/jsrsasign/api/symbols/global__.html#.isBase64URLDot https://github.com/kjur/jsrsasign/wiki/Tutorial-for-JWS-verification https://github.com/kjur/jsrsasign/wiki/Tutorial-for-JWT-verification https://security.snyk.io/vuln/SNYK-JS-JSRSASIGN-2869122

Record
GHSA-3fvg-4v2m-98jf
CVSS 3.1
8.6 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:H/A:N
Weakness
CWE-347
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
jsrsasign
npm
4.8.0 up to 10.5.25
10.5.25

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-2022-25898 is a high vulnerability (CVSS 7.7) in Kjur Jsrsasign, published June 25, 2022. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.15%, the 67th percentile. Fixed in jsrsasign 10.5.25.

References

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