Description
gunicorn version 19.4.5 contains a CWE-113: Improper Neutralization of CRLF Sequences in HTTP Headers vulnerability in "process_headers" function in "gunicorn/http/wsgi.py" that can result in an attacker causing the server to return arbitrary HTTP headers. This vulnerability appears to have been fixed in 19.5.0.
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 | gunicorn | 19.5.0-1 | — |
| Debian 13 | gunicorn | 19.5.0-1 | — |
| Debian 12 | gunicorn | 19.5.0-1 | — |
| Debian 8 | gunicorn | 19.0-1+deb8u1 | DSA-4186-1 |
| Debian 7 | gunicorn | 0.14.5-3+deb7u2 | DLA-1357-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 16.04 LTS | gunicorn | 19.4.5-1ubuntu1.1 | USN-4022-1 |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 14.04 LTS | gunicorn | 17.5-2ubuntu0.1~esm1 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | gunicorn | < 19.5.0 | 19.5.0 | GHSA-32pc-xphx-q4f6 |
Advisories 3
- DSA-4186-1 gunicorn - security update Debian Security (DSA / DLA) · Mar 9, 2026
- DLA-1357-1 gunicorn - security-update Debian Security (DSA / DLA) · Mar 9, 2026
- USN-4022-1 Gunicorn vulnerability Ubuntu Security Notices (USN) · Feb 10, 2026