GHSA-r9jw-mwhq-wp62 CVE-2017-11424 PYSEC-2017-24
PyJWT vulnerable to key confusion attacks
- Severity
- 7.5 / 10
- High · CVSS 3.0
- Exploit chance (EPSS)
- 1.80%
- Chance of exploitation in the next 30 days. Higher than 78.55% of scored vulnerabilities.
- Known exploited
- No
- Not in CISA's catalog
- Weakness
- —
- Not classified
- Fix
1.5.1- Upgrade pyjwt to this version or later
Description
In PyJWT 1.5.0 and below the invalid_strings check in HMACAlgorithm.prepare_key does not account for all PEM encoded public keys. Specifically, the PKCS1 PEM encoded format would be allowed because it is prefaced with the string -----BEGIN RSA PUBLIC KEY----- which is not accounted for. This enables symmetric/asymmetric key confusion attacks against users using the PKCS1 PEM encoded public keys, which would allow an attacker to craft JWTs from scratch.
Affected versions
PyPI
| Package | Vulnerable | Fixed in |
|---|---|---|
| pyjwt | < 1.5.1 |
1.5.1 |
How to fix
Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.
pyjwt PyPI → 1.5.1
- pip
pip install --upgrade "pyjwt>=1.5.1"- poetry
poetry add "pyjwt>=1.5.1"- uv
uv add "pyjwt>=1.5.1"
Severity breakdown
CVSS 3.0 7.5
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
References
Advisories
Packages
Other links
Timeline
- Published
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GHSA-pxh4-856f-4h89 PyJWT: HS256/384/512 verify accepts empty HMAC key via oct JWK (PyJWK/PyJWKClient) enabling token forgery | High | Also affects pyjwt |
| GHSA-gvp8-978c-rx2q PyJWT.decode() reintroduces options-dict mutation, enabling silent claim-verification bypass on dict reuse | Medium | Also affects pyjwt |
| GHSA-x33g-cr3x-6449 PyJWT accepts inconsistent OKP x/d JWKs, causing public/private key identity confusion | High | Also affects pyjwt |
| GHSA-w6j9-cwv2-h6wq PyJWT: Malformed RSA JWK aborts parsing of an entire JWK Set | High | Also affects pyjwt |
| GHSA-w2cx-738m-mc7w PyJWT accepts public JWK containers as HMAC secrets | High | Also affects pyjwt |
| GHSA-r6x4-923q-g947 PyJWT BOM Bypass | High | Also affects pyjwt |
| GHSA-p4g4-x82p-q773 PyJWT: Public keys in DER form are accepted as HMAC secrets, bypassing the CVE-2022-29217 guard | High | Also affects pyjwt |
| GHSA-jwrc-g2q2-pq5p PyJWT: ReDoS vulnerability when calling the `is_pem_format` function. | Medium | Also affects pyjwt |
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