Description
Authlib is a Python library which builds OAuth and OpenID Connect servers. Prior to version 1.6.9, a cryptographic padding oracle vulnerability was identified in the Authlib Python library concerning the implementation of the JSON Web Encryption (JWE) RSA1_5 key management algorithm. Authlib registers RSA1_5 in its default algorithm registry without requiring explicit opt-in, and actively destroys the constant-time Bleichenbacher mitigation that the underlying cryptography library implements correctly. This issue has been patched in version 1.6.9.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| authlib | authlib | < 1.6.9 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | python-authlib | 1.6.9-1 | — |
| Debian 13 | python-authlib | No fix yet | — |
| Debian 12 | python-authlib | 1.2.0-1+deb12u2 | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | python-authlib | No fix yet | — |
| Ubuntu 25.10 | python-authlib | No fix yet | — |
Show 3 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | python-authlib | 1.6.7-1ubuntu0.1~esm1 | USN-8557-1 |
| Ubuntu Pro 24.04 LTS | python-authlib | 1.3.0-1ubuntu0.1~esm2 | USN-8557-1 |
| Ubuntu Pro 22.04 LTS | python-authlib | 0.15.5-1ubuntu0.1~esm2 | USN-8557-1 |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES 15 SP6 | python-Authlib | 1.3.1-150600.3.17.1 | SUSE-SU-2026:0975-1 |
| SLES 3 | python-Authlib | 1.3.1-150600.3.17.1 | SUSE-SU-2026:0975-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SLES for SAP 15 SP6 | python-Authlib | 1.3.1-150600.3.17.1 | SUSE-SU-2026:0975-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | python-Authlib | 1.5.2-bp160.3.1 | openSUSE-SU-2026:20392-1 |
| openSUSE Leap 15.6 | python-Authlib | 1.3.1-150600.3.17.1 | SUSE-SU-2026:0975-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | authlib | < 1.6.9 | 1.6.9 | GHSA-7432-952r-cw78 |
Advisories 3
- USN-8557-1 python-authlib vulnerabilities Ubuntu Security Notices (USN) · Jul 17, 2026
- openSUSE-SU-2026:20392-1 Security update for python-Authlib SUSE / openSUSE Security Updates · Mar 26, 2026
- SUSE-SU-2026:0975-1 Security update for python-Authlib SUSE / openSUSE Security Updates · Mar 25, 2026