CVE-2026-75856Public exploitNetwork attack vector

SSRF bypass via DNS failure TOCTOU

Published Aug 18, 2026 · Updated Aug 18, 2026

Server-side request forgery in Hmbown CodeWhale before 0.8.64 allows attackers to reach internal IP addresses via crafted DNS replies. In fetch_url preflight validation, validate_fetch_target called lookup_host and validated returned addresses, but if DNS resolution failed or yielded no address it still allowed the later HTTP request to run instead of aborting. Exploitation requires control of DNS answers for an attacker-chosen hostname; the published PoC returns NXDOMAIN on the first A and AAAA lookups and then resolves the follow-on request to 127.0.0.1, demonstrating SSRF-based reads of local or private-network services.

CVSS severity8.6
High
EPSS probability0.46%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Server-side request forgery in Hmbown CodeWhale before 0.8.64 allows attackers to reach internal IP addresses via crafted DNS replies. In fetch_url preflight validation, validate_fetch_target called lookup_host and validated returned addresses, but if DNS resolution failed or yielded no address it still allowed the later HTTP request to run instead of aborting. Exploitation requires control of DNS answers for an attacker-chosen hostname; the published PoC returns NXDOMAIN on the first A and AAAA lookups and then resolves the follow-on request to 127.0.0.1, demonstrating SSRF-based reads of local or private-network services.

The record

CVE
CVE-2026-75856
Published
Aug 18, 2026
Updated
Aug 18, 2026
Vendor
Shannon Labs
Product
CodeWhale
Classifications
CWE-918
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 18, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.8.41 <0.8.64
  2. Affected versionversion=0.8.5 <0.8.41

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Shannon Labs · CodeWhaleversion=0.8.41 <0.8.64; version=0.8.5 <0.8.41

Published CVSS scores

8.6GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-918Server-Side Request Forgery (SSRF)

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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