CVE-2021-39286 Cross-site scripting in pywb
Cross-site scripting vulnerability in pywb allows attackers to execute arbitrary scripts due to missing autoescaping in Jinja2 templates.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- A user has to click or open something
- Fix
- Available
What is CVE-2021-39286?
CVE-2021-39286 is a medium-severity cross-site scripting vulnerability in n/a, published on 18 Aug 2021. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.
Official description
Webrecorder pywb before 2.6.0 allows XSS because it does not ensure that Jinja2 templates are autoescaped.
Weakness: CWE-79
Which versions are affected by CVE-2021-39286?
3 open source packages ship an affected version, including pywb. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
pywb PyPI | All versions | 2.6.0 |
pywb PyPI | All versions | 2.6.0 |
pywb PyPI | All versions | 2.6.0 |
Products include Webrecorder Pywb.
How do I fix CVE-2021-39286?
Upgrade pywb to 2.6.0 or later.
Escape output for the context it lands in and set a strict Content Security Policy. Upgrading the affected component is the real fix. More about Cross-site scripting.
Is CVE-2021-39286 being exploited?
There is no known exploitation of CVE-2021-39286 in the wild and no public exploit code.
Sources
Also known as GHSA-947x-pv47-pp3q, PYSEC-2021-120.