Vulnerability in github.com/fatedier/frp (CVE-2026-73564)
Summary
Vulnerability in github.com/fatedier/frp (CVE-2026-73564). Risk of unauthorized operations or information disclosure. Exploitable via frps. Mitigation: upgrade to 0.70.1 or later.
Original description
The description as published by the source.
Summary
An integer-overflow vulnerability in the frp server's optional SSH Tunnel Gateway lets any unauthenticated remote attacker crash the entire frps process with a single five-byte message. When the gateway parses an SSH exec channel request in pkg/ssh/server.go, it adds a small constant to a four-byte length value taken directly from the request. Because that length is fully attacker-controlled, a value of 0xFFFFFFFF makes the addition wrap around to a tiny number, defeating the only bounds check and forcing an out-of-range slice. Go raises a panic that nothing recovers, so the whole server exits. In the default gateway mode SSH clients are not authenticated and the request is handled before any frp token is checked, so the crash is reachable pre-authentication. It carries no state and is trivially repeatable, turning one crash into a sustained outage that drops every tunnel for every user.
Details
The exec request payload is a four-byte big-endian length followed by that many command bytes, and the length field is fully attacker-controlled. The gateway computes the end of the command as 4 + length. The constant 4 takes the uint32 type of the length field, so 4 + 0xFFFFFFFF wraps modulo 2^32 to 3. The only guard compares the real payload size against this wrapped value, so a five-byte payload passes the test 5 < 3, and the slice runs from index 4 to index 3:
// pkg/ssh/server.go:315-319
end := 4 + binary.BigEndian.Uint32(req.Payload[…
Source: GitHub Security Advisories (Global) NVD GitHub Advisory
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-2026-73564 has been found in github.com/fatedier/frp.
Attackers can target a specific entry point like frps over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: upgrade github.com/fatedier/frp to 0.70.1 or later.
If unsure, ask your IT team or search "github.com/fatedier/frp CVE-2026-73564" on the vendor's site.
CVE-2026-73564 (github.com/fatedier/frp) — CWE-129
Attack surface: frps / exec / uint32 / recover
Patched: 0.70.1 — 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-129) exists in github.com/fatedier/frp. Attackers reach the vulnerable code path via frps.
Check the vendor advisory for the affected versions of github.com/fatedier/frp. Attack surface: frps / exec / uint32 / recover.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 0.70.1.
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 'github.com/fatedier/frp' . 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
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1Identify exposure identify
grep -r 'github.com/fatedier/frp' . | 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
github.com/fatedier/frp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 github.com/fatedier/frp to 0.70.1ステージング環境で 0.70.1 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
- package github.com
- web github.com
- web github.com
- web github.com
- web github.com
- web github.com