Vulnerability in emmett-core (CVE-2026-25577)
Summary
Vulnerability in emmett-core (CVE-2026-25577). Risk of unauthorized operations or information disclosure. Exploitable via Cookie header. Mitigation: upgrade to 1.3.11 or later.
Original description
The description as published by the source.
Summary
The cookies property in emmett_core.http.wrappers.Request does not handle
CookieError exceptions when parsing malformed Cookie headers. This allows
unauthenticated attackers to trigger HTTP 500 errors and cause denial of service.
Details
Location: emmett_core/http/wrappers/__init__.py (line 64)
Vulnerable Code:
@cachedprop
def cookies(self) -> SimpleCookie:
cookies: SimpleCookie = SimpleCookie()
for cookie in self.headers.get("cookie", "").split(";"):
cookies.load(cookie) # No exception handling
return cookies
PoC
Sending cookies containing special characters such as /(){} will result in insufficient error handling and a server error.
$ curl -w "\nTime: %{time_total}s\n" http://localhost:8000/ -H "Cookie:/security=test"
Internal error
Time: 0.024363s
After the same error occurs several times, the server cannot process it normally.
$ curl -w "\nTime: %{time_total}s\n" http://localhost:8000/ -H "Cookie:(security=test"
Internal error
Time: 60.069334s
$ curl -w "\nTime: %{time_total}s\n" http://localhost:8000/ -H "Cookie:security=test"
Internal error
Time: 60.074031s
This is server log.
[2026-02-03 08:23:40,541] ERROR in handlers: Application exception:
Traceback (most recent call last):
File "/home/geonwoo/.local/lib/python3.13/site-packages/emmett/rsgi/handlers.py", line 70, in dynamic_handler
http = await self.router.dispatch(request, response)
^^^^^^…
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-2026-25577 has been found in emmett-core.
Attackers can target a specific entry point like Cookie header over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade emmett-core to 1.3.11 or later.
If unsure, ask your IT team or search "emmett-core CVE-2026-25577" on the vendor's site.
CVE-2026-25577 (emmett-core) — CWE-248
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Cookie header / cookies / emmett_core.http.wrappers.Request / CookieError
Patched: 1.3.11 — 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-248) exists in emmett-core. Attackers reach the vulnerable code path via Cookie header without authentication.
Check the vendor advisory for the affected versions of emmett-core. Attack surface: Cookie header / cookies / emmett_core.http.wrappers.Request / CookieError.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 1.3.11.
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 'emmett-core' . 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 'emmett-core' . | 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
emmett-core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 emmett-core to 1.3.11ステージング環境で 1.3.11 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 github.com