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Fencer Vulns
medium 4.8

CVE-2026-33621 json

PinchTab: Unapplied Rate Limiting Middleware Allows Unbounded Brute-Force of API Token

published 2026-03-24 7 mo ago modified 2026-06-17 4 mo ago also EUVD-2026-16403 , GHSA-j65m-hv65-r264 , GO-2026-4821

cvss
4.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 25%
public exploits
0
none known

Summary

PinchTab is a standalone HTTP server that gives AI agents direct control over a Chrome browser. PinchTab `v0.7.7` through `v0.8.4` contain incomplete request-throttling protections for auth-checkable endpoints. In `v0.7.7` through `v0.8.3`, a fully implemented `RateLimitMiddleware` existed in `internal/handlers/middleware.go` but was not inserted into the production HTTP handler chain, so requests were not subject to the intended per-IP throttle. In the same pre-`v0.8.4` range, the original limiter also keyed clients using `X-Forwarded-For`, which would have allowed client-controlled header spoofing if the middleware had been enabled. `v0.8.4` addressed those two issues by wiring the limiter into the live handler chain and switching the key to the immediate peer IP, but it still exempted `/health` and `/metrics` from rate limiting even though `/health` remained an auth-checkable endpoint when a token was configured. This issue weakens defense in depth for deployments where an attacker can reach the API, especially if a weak human-chosen token is used. It is not a direct authentication bypass or token disclosure issue by itself. PinchTab is documented as local-first by default and uses `127.0.0.1` plus a generated random token in the recommended setup. PinchTab's default deployment model is a local-first, user-controlled environment between the user and their agents; wider exposure is an intentional operator choice. This lowers practical risk in the default configuration, even though it does not by itself change the intrinsic base characteristics of the bug. This was fully addressed in `v0.8.5` by applying `RateLimitMiddleware` in the production handler chain, deriving the client address from the immediate peer IP instead of trusting forwarded headers by default, and removing the `/health` and `/metrics` exemption so auth-checkable endpoints are throttled as well.

Patch / fix

  • go github.com/pinchtab/pinchtab 0.8.5
  • pinchtab pinchtab 0.8.5
  • govulncheck-vulndb openSUSE Leap 15.6 0.0.20260326T203309-150000.1.155.2

suse advisories SUSE-SU-2026:1135-1

  • govulncheck-vulndb openSUSE Leap 16.0 0.0.20260723T184607-160000.1.1

opensuse advisories openSUSE-SU-2026:21483-1

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
partial
Assessed
7 mo ago

Exploit prediction

0.32% chance of exploitation in the next 30 days, higher than 25% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/pinchtab/pinchtab/security/advisories/GHSA-j65m-hv65-r264 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 3.1 4.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
GitHub 3.1 4.8 CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N
NVD 3.1 6.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

Affected packages

ecosystem package affected fixed in
go github.com/pinchtab/pinchtab
>=0.7.7, <0.8.5
0.8.5

Affected products

  • pinchtab pinchtab

Classification

Weakness
  • CWE-290 Authentication Bypass by Spoofing
  • CWE-770 Allocation of Resources Without Limits or Throttling

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.