---
title: "CVE-2026-75856: CodeWhale: SSRF‌ bypass - TOCTOU on DNS failure for DNS pinning"
url: https://erroneo.us/security/cve/CVE-2026-75856/
description: "CVE-2026-75856 (deepseek-tui (crates.io (Rust))): CodeWhale before 0.8.64 contains a server-side request forgery bypass vulnerability in DNS pinning logic…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-08-18
date_modified: 2026-09-04
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-75856"
kev: false
cvss: 9.2
epss: 0.00495
license: All rights reserved. Quote with attribution and a link.
---

# CVE-2026-75856: CodeWhale: SSRF‌ bypass - TOCTOU on DNS failure for DNS pinning

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- Not in CISA KEV , but CISA’s SSVC assessment records a public proof-of-concept, so attack code exists.
- EPSS 0.5% , percentile 41: FIRST’s model estimates a 0.5% chance of exploitation activity in the next 30 days, higher than 41% of all scored CVEs (low). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes deepseek-tui (crates.io (Rust)) >= 0.8.5, <= 0.8.41, no fixed version listed ; deepseek-tui (npm) >= 0.8.5, < 0.8.41, fixed in 0.8.41 ; codewhale-tui (crates.io (Rust)) >= 0.8.41, < 0.8.64, fixed in 0.8.64 ; codewhale (npm) >= 0.8.41, < 0.8.64, fixed in 0.8.64 . Check your lockfile, including transitive dependencies.

## What it is

CodeWhale before 0.8.64 contains a server-side request forgery bypass vulnerability in DNS pinning logic that fails to prevent time-of-check-time-of-use attacks. Attackers can manipulate DNS responses to fail initial resolution checks and succeed on secondary requests, allowing requests to internal IP addresses and bypassing SSRF mitigations.

## Affected packages

- crates.io (Rust) `deepseek-tui` >= 0.8.5, <= 0.8.41 → fixed: none listed
- npm `deepseek-tui` >= 0.8.5, < 0.8.41 → fixed: 0.8.41
- crates.io (Rust) `codewhale-tui` >= 0.8.41, < 0.8.64 → fixed: 0.8.64
- npm `codewhale` >= 0.8.41, < 0.8.64 → fixed: 0.8.64

## Affected products (CVE record)

- Hmbown CodeWhale: 0.8.5 < 0.8.41
- Hmbown CodeWhale: 0.8.5 < 0.8.41
- Hmbown CodeWhale: 0.8.41 < 0.8.64
- Hmbown CodeWhale: 0.8.41 < 0.8.64

## Severity

- VulnCheck CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N`
- VulnCheck CVSS 3.1: 8.6 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N`
- GitHub CVSS 4.0: 9.2 `CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation poc , automatable yes , technical impact partial .
- FIRST EPSS (model of 2026-10-21): 0.50% probability of exploitation activity in the next 30 days; percentile 41.

## Sources

- [GitHub Security Advisory (GHSA-6v2g-fpxh-pmmh)](https://github.com/Hmbown/CodeWhale/security/advisories/GHSA-6v2g-fpxh-pmmh)
- [Patch Commit](https://github.com/Hmbown/CodeWhale/commit/26de44a8bd5051f8f944ea60b2c37ae1d2b7d25e)
- [GitHub Advisory GHSA-6v2g-fpxh-pmmh](https://github.com/advisories/GHSA-6v2g-fpxh-pmmh)
- [CVE.org record CVE-2026-75856](https://www.cve.org/CVERecord?id=CVE-2026-75856)
- [NVD entry CVE-2026-75856](https://nvd.nist.gov/vuln/detail/CVE-2026-75856)
- [VulnCheck Advisory: CodeWhale before 0.8.64 SSRF Bypass via DNS Pinning TOCTOU](https://www.vulncheck.com/advisories/codewhale-before-ssrf-bypass-via-dns-pinning-toctou)

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Source page: https://erroneo.us/security/cve/CVE-2026-75856/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt