Vulnerability in litestar (CVE-2026-25479)
Summary
Vulnerability in litestar (CVE-2026-25479). Risk of unauthorized operations or information disclosure. Exploitable via Host header. Mitigation: upgrade to 2.20.0 or later.
Original description
The description as published by the source.
Summary
AllowedHosts host validation can be bypassed because configured host patterns are turned into regular expressions without escaping regex metacharacters (notably .). A configured allowlist entry like example.com can match exampleXcom
Details
In litestar.middleware.allowed_hosts, allowlist entries are compiled into regex patterns in a way that allows regex metacharacters to retain special meaning (e.g., . matches any character). This enables a bypass where an attacker supplies a host that matches the regex but is not the intended literal hostname.
PoC
Server (poc_allowed_hosts_server.py)
from litestar import Litestar, get
from litestar.middleware.allowed_hosts import AllowedHostsConfig
@get("/")
async def index() -> str:
return "ok"
config = AllowedHostsConfig(allowed_hosts=["example.com"])
app = Litestar([index], allowed_hosts_config=config)
uvicorn poc_allowed_hosts_server:app --host 127.0.0.1 --port 8001
Client (poc_allowed_hosts_client.py)
import http.client
def req(host_header: str) -> tuple[int, bytes]:
c = http.client.HTTPConnection("127.0.0.1", 8001, timeout=3)
c.request("GET", "/", headers={"Host": host_header})
r = c.getresponse()
body = r.read()
c.close()
return r.status, body
print("evil.com:", *req("evil.com"))
print("exampleXcom:", *req("exampleXcom"))
Expected (vulnerable behavior):
Host: evil.com → 400 invalid host
Host: exampleXcom → 200 ok (bypass)
Impact
Type: security control…
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-25479 has been found in litestar.
Attackers can target a specific entry point like Host header over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade litestar to 2.20.0 or later.
If unsure, ask your IT team or search "litestar CVE-2026-25479" on the vendor's site.
CVE-2026-25479 (litestar) — CWE-185
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Host header
Patched: 2.20.0 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-185) exists in litestar. Attackers reach the vulnerable code path via Host header without authentication.
Check the vendor advisory for the affected versions of litestar. Attack surface: Host header.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 2.20.0.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'litestar' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'litestar' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
litestarを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade litestar to 2.20.0ステージング環境で 2.20.0 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- package github.com
- web github.com
- web github.com
- web docs.litestar.dev
- web github.com