Description
bleach.clean behavior parsing style attributes could result in a regular expression denial of service (ReDoS). Calls to bleach.clean with an allowed tag with an allowed style attribute are vulnerable to ReDoS. For example, bleach.clean(..., attributes={'a': ['style']}).
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Mozilla | Mozilla Bleach | unspecified – < 3.1.4 | 3.1.4 |
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-bleach | 3.1.4-1 | — |
| Debian 13 | python-bleach | 3.1.4-1 | — |
| Debian 12 | python-bleach | 3.1.4-1 | — |
| Debian 8 | python-bleach | 1.4-1+deb8u1 | DLA-2167-1 |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | python-bleach | 3.1.1-1ubuntu0.1~esm1 | — |
| Ubuntu Pro 18.04 LTS | python-bleach | 2.1.2-1ubuntu0.1~esm1 | — |
| Ubuntu Pro 16.04 LTS | python-bleach | 1.4.2-1ubuntu0.1~esm1 | — |
SUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| SUSE Package Hub 15 SP2 | python-bleach | 3.1.5-bp152.2.4.1 | openSUSE-SU-2021:0571-1 |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Tumbleweed | python-bleach | 6.1.0-1.5 | openSUSE-SU-2026:11323-1, openSUSE-SU-2024:14134-1 |
| openSUSE Leap 15.2 | python-bleach | 3.1.5-lp152.2.3.1 | openSUSE-SU-2021:0552-1 |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | bleach | < 3.1.4 | 3.1.4 | GHSA-vqhp-cxgc-6wmm |
Advisories 5
- openSUSE-SU-2026:11323-1 python313-bleach-6.4.0-1.1 on GA media SUSE / openSUSE Security Updates · Jul 22, 2026
- DLA-2167-1 python-bleach - security update Debian Security (DSA / DLA) · Mar 9, 2026
- openSUSE-SU-2021:0571-1 Security update for python-bleach SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2021:0552-1 Security update for python-bleach SUSE / openSUSE Security Updates · Feb 4, 2026
- openSUSE-SU-2024:14134-1 python310-bleach-6.1.0-1.5 on GA media SUSE / openSUSE Security Updates · May 7, 2025