Security Digest · Vulnerability record
CVE-2026-75856: CodeWhale: SSRF bypass - TOCTOU on DNS failure for DNS pinning
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.
CVSS 9.2 Critical EPSS 0.5% · p41
Should you act?
Critical and remotely reachable
No known exploitation yet, but it is network-reachable without credentials. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- 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.
From the GitHub advisory
Maintainer resolution
The CodeWhale maintainers validated this report. The affected package ranges are recorded in the advisory metadata. Version 0.8.64 contains the fix in commit 26de44a8bd5051f8f944ea60b2c37ae1d2b7d25e. Users should upgrade to 0.8.64 or later. The original reporter analysis is preserved below.
Summary DNS-pinning failure allows natural failure of code, however with a custom DNS server that fails the initial requests and allows the secondary requests, it's possible to bypass the logic.
Details Simplified attack scenario: 1. Attacker asks agent to visit the mydomain.com. 2. CodeWhale tries to resolve the IP of mydomain.com, however, the custom DNS server that's controlled by the attacker marks the request DNS query as failed (Time of Check). 3. CodeWhale allows the code to continue as it expects it request to fail again. 4. On the secondary (Time of Use), the DNS server resolves mydomain.com to a local IP (e.g., 127.0.0.1) 5. The request is executed and the content from port 80 is returned to the attacker, allowing full bypass of SSRF mitigations.
In the DNS-pinning section, when DNS fails, the code is allowed to continue as it's expected to fail. However
Weakness type: CWE-918.
Product: deepseek-tui (crates.io (Rust)) · Assigned by: VulnCheck · Published: 2026-08-18
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| crates.io (Rust) | deepseek-tui | >= 0.8.5, <= 0.8.41 | none listed |
| npm | deepseek-tui | >= 0.8.5, < 0.8.41 | 0.8.41 |
| crates.io (Rust) | codewhale-tui | >= 0.8.41, < 0.8.64 | 0.8.64 |
| npm | codewhale | >= 0.8.41, < 0.8.64 | 0.8.64 |
| Vendor | Product | Affected versions (per 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 scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulnCheck | 4.0 | 9.2 Critical | 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 | 3.1 | 8.6 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N |
| GitHub | 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 |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Attack requirements: none
- Privileges required: none (no login)
- User interaction: none
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- 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.
Timeline
- — CVE record last updated
- — CVE record published by VulnCheck
- — GitHub-reviewed advisory GHSA-6v2g-fpxh-pmmh published (critical)
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vendor and project advisories, patches
- GitHub Security Advisory (GHSA-6v2g-fpxh-pmmh) github.com
- Patch Commit github.com
Vulnerability records
- GitHub Advisory GHSA-6v2g-fpxh-pmmh github.com
- CVE.org record CVE-2026-75856 cve.org
- NVD entry CVE-2026-75856 nvd.nist.gov