Description
NLTK before 3.10.3 contains an uncontrolled recursion vulnerability in nltk.featstruct.FeatStructReader that allows unauthenticated attackers to cause a denial of service by supplying deeply nested feature-structure input. Attackers can craft trivial payloads with nested brackets that exceed Python's recursion limit and raise an unhandled RecursionError, crashing applications that parse user-supplied feature structures or feature grammars.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| nltk | nltk | < 3.10.3 | 3.10.3 |
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 | nltk | 3.10.3-1 | — |
| Debian 13 | nltk | No fix yet | — |
| Debian 12 | nltk | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 24.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 22.04 LTS | nltk | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 20.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 18.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 16.04 LTS | nltk | No fix yet | — |
| Ubuntu Pro 14.04 LTS | nltk | No fix yet | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | open-webui | 0.11.3-r1 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| PyPI | nltk | < 3.10.3 | 3.10.3 | GHSA-cw6x-m8jw-qmrh |
References
- GitHub Security Advisory (GHSA-cw6x-m8jw-qmrh) vendor-advisory
- VulnCheck Advisory: NLTK before 3.10.3 Denial of Service via Uncontrolled Recursion third-party-advisory