CVE-2026-47066: benoitc hackney · Infinite Loop
Affects benoitc hackneySource CVE Database V5
Not known to be exploited · CVSS 8.7 High : upgrade to 4.0.1 soon.
Data as of 26 Oct 2026, 09:16 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 54% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 4.0.1, e548aba1f97ffa3f4750da7b772998fb78c01894
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 25 May 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by 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 26 Oct 2026.
What to do
Upgrade hackney to 4.0.1; hackney to e548aba1f97ffa3f4750da7b772998fb78c01894.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| benoitchackney | Affected
| Fixed in
|
| benoitchackney | Affected
| Fixed in
|
Hexhackneypkg:hex/hackneyOther threats | Affected
| Fixed in
|
Hexhackneypkg:hex/hackneyOther threats | Affected
| Fixed in
|
CPE configurations (1)
cpe:2.3:a:benoitc:hackney:*:*:*:*:*:*:*:*
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Description
Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in benoitc hackney allows Excessive Allocation. The Alt-Svc response header parser in src/hackney_altsvc.erl does not guarantee forward progress. When parse_token/2 receives a non-token, non-whitespace, non-comma byte (e.g. !, @, =, ;), it returns the input unchanged.skip_comma/1 also returns the buffer unchanged when the first byte is not a comma.parse_entries/2 then recurses with identical data, creating a tight infinite tail-recursive loop that pins a scheduler at 100% CPU. The calling process never returns. The entry point parse_and_cache/3 is called synchronously in the connection process on every HTTP response. A single-byte Alt-Svc: ! response header is sufficient to trigger the hang; the header is fully controlled by any HTTP origin the client connects to. This issue affects hackney: from 2.0.0-beta.1 before 4.0.1.
References
- github.com/benoitc/hackney/security/advisories/GHSA-6cp8-v795-jr2j (opens in a new tab)
- cna.erlef.org/cves/CVE-2026-47066.html (opens in a new tab)
- osv.dev/vulnerability/EEF-CVE-2026-47066 (opens in a new tab)
- github.com/benoitc/hackney/commit/e548aba1f97ffa3f4750da7b772998fb78c01894 (opens in a new tab)