CVE-2022-25898
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.
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
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 High
CVSS: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 High
CVSS: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 High
CVSS: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 High
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:L/I:L/A:H - CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - CVSS 2.0
- 7.5 High
AV: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 High
CVSS: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 High
CVSS: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
| Package | Affected | Fixed |
|---|---|---|
jsrsasignnpm |
4.8.0 up to 10.5.25 | 10.5.25 |
History
| Recorded | Changed | Sources |
|---|---|---|
| aliases | EUVD | |
| first indexed | CVE 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
snyk.io/vuln/SNYK-JS-JSRSASIGN-2869122
snyk.io/vuln/SNYK-JAVA-ORGWEBJARSNPM-2935896
snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWERGITHUBKJUR-2935897
snyk.io/vuln/SNYK-JAVA-ORGWEBJARSBOWER-2935898
github.com/kjur/jsrsasign/commit/4536a6e9e8bcf1a644ab7c07ed96e453347dae41
github.com/kjur/jsrsasign/releases/tag/10.5.25