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VulnerabilityPublished Updated

CVE-2026-47076: benoitc hackney · Interpretation Conflict

Affects benoitc hackneySource CVE Database V5

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Not known to be exploited · CVSS 6.9 Medium : upgrade to 4.0.1 when convenient.

Data as of 30 Oct 2026, 11:52 UTC

CVSS 4.0 base score
6.9Medium
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 13% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch
Available – fixed in 4.0.1, 452620a92ec1da2e6b4862a049a2a4f04b42068f
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:H/VI:N/VA:N/SC:H/SI:N/SA:N

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 May 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponized: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 30 Oct 2026.

What to do

Upgrade hackney to 4.0.1; hackney to 452620a92ec1da2e6b4862a049a2a4f04b42068f.

Affected software

ProductAffectedFixed in
benoitchackneyAffected
  • >=0.13.0 <4.0.1
Fixed in
  • 4.0.1
benoitchackneyAffected
  • ≥ 4d725507588942fd00efca15b86da3273656510a, < 452620a92ec1da2e6b4862a049a2a4f04b42068f
Fixed in
  • 452620a92ec1da2e6b4862a049a2a4f04b42068f
Hexhackneypkg:hex/hackneyOther threatsAffected
  • =0.13.0
Fixed in–
Hexhackneypkg:hex/hackneyOther threatsAffected
  • >=0.13.0 <4.0.1
Fixed in
  • 4.0.1

CPE configurations (1)

  • cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

If you cannot patch yet, users should consider implementing additional validation on URLs before passing them to hackney, specifically normalizing and validating host components consistently to prevent percent-encoding bypass. Monitoring vendor channels for updates and upgrading to hackney versions 4.0.1 or later once released is recommended.

Description

Interpretation Conflict vulnerability in benoitc hackney allows Server Side Request Forgery.hackney_url:normalize/2 URL-decodes the host component after the URL has been parsed into a #hackney_url{} record. OTP's uri_string:parse/1 and inet:parse_address/1 do not decode percent-escapes in the host, so a URL such as http://%31%32%37%2E%30%2E%30%2E%31/ is seen by a caller's allowlist validator with host %31%32%37%2E%30%2E%30%2E%31 (not an IP address), which passes the allowlist check.hackney's normalizer then decodes the host to 127.0.0.1 and opens a TCP connection to loopback. Because hackney:request/5 always calls hackney_url:normalize/2 with no opt-out, every request that takes a binary or list URL is affected. The same technique reaches cloud instance metadata services (169.254.169.254), RFC1918 networks, and any admin interface listening on localhost. This issue affects hackney: from 0.13.0 before 4.0.1.

References

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