CVE-2026-126193 Denial of service in soupsieve
Deeply nested CSS selectors can exhaust the Python stack in apps using Soup Sieve, crashing the request.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Harmful if only installed
- No
- Needs a specific call
- Yes
- Fix
- None listed
What is CVE-2026-126193?
CVE-2026-126193 is a medium-severity denial of service vulnerability in facelessuser soupsieve, published on 12 Nov 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Soup Sieve is a CSS selector library for Beautiful Soup. From 0.4 until 3.0, deeply nested CSS pseudo-class selectors can cause recursive parsing to exceed Python’s recursion limit and raise RecursionError . Applications accepting untrusted selectors may experience failure of the affected request or task if the exception is not handled. The demonstrated behavior is recoverable and does not establish an interpreter crash or persistent service-wide denial of service. This vulnerability is fixed in version 3.0.
Weakness: CWE-674
Which versions are affected by CVE-2026-126193?
An affected version is only exploitable if your software uses the vulnerable function or option. Many projects that include it are not exposed.
How do I fix CVE-2026-126193?
No fix has been published for CVE-2026-126193 yet. Limit exposure of the affected software until one is available.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-126193 being exploited?
There is no known exploitation of CVE-2026-126193 in the wild and no public exploit code.
Sources
Also known as GHSA-7g44-g9rc-x53w.