Critical, CVSS 9.3PyPIAmendedPublished
python-jwt vulnerable to token forgery with new claims
CVE-2022-39227 · GHSA-5p8v-58qm-c7fp
- Affected
- PyPI python-jwt < 3.3.4
- Fixed in
- 3.3.4· Vendor fix available
- Issue
- Impact An attacker who obtains a JWT can arbitrarily forge its contents without knowing the secret key. Depending on the application, this may for example enable the attacker to spoof other user's identities, hijack their sessions, or bypass authentication. Patches Users should upgrade to version 3.3.4 Fixed by: https://github.com/davedoesdev/python-jwt/commit/88ad9e67c53aa5f7c43ec4aa52ed34b7930068c9 Workarounds None References Found by Tom Tervoort https://github.com/pypa/advisory-database/blob/main/vulns/python-jwt/PYSEC-2022-259.yaml More information The vulnerability allows an attacker, who possesses a single valid JWT, to create a new token with forged claims that the verifyjwt function will accept as valid. The issue is caused by an inconsistency between the JWT parsers used by python-jwt and its dependency jwcrypto. By mixing compact and JSON representations, an attacker can trick jwcrypto of parsing different claims than those over which a signature is validated by jwcrypto.…
Recommended action: Upgrade to 3.3.4 or later, then redeploy and verify.A vendor fix does not resolve your finding until you verify it in your own systems.