CVE-2026-47077 json
Unbounded body accumulation in HTTP/3 response loop in hackney
published 2026-05-25 5 mo ago modified 2026-09-08 2 mo ago also EEF-CVE-2026-47077 , GHSA-jq4m-q6p2-8gwc , EUVD-2026-31688
- cvss
- 7.5
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.7%
- EPSS 0.7% chance of exploitation in 30 days, percentile 53%
- public exploits
- 0
- none known
Summary
Allocation of Resources Without Limits or Throttling vulnerability in benoitc hackney allows Flooding. hackney_h3:await_response_loop/6 accumulates the HTTP/3 response body in memory without any size cap. The after Timeout clause is a per-message inactivity timer that resets on every received chunk, housekeeping message, or settings frame — it is not a wall-clock deadline. A malicious HTTP/3 server that emits one small chunk every Timeout - 1 ms with Fin = false and never sends a final frame keeps the loop alive indefinitely while the accumulation buffer grows linearly without bound, eventually exhausting the BEAM process heap and causing an out-of-memory condition.
This issue affects hackney: from 2.0.0 before 4.0.1.
Patch / fix
- hex hackney 4.0.1
- benoitc hackney 4.0.1
CISA SSVC
- Exploitation
- Proof of concept is public
- Automatable
- yes
- Technical impact
- partial
- Assessed
- 5 mo ago
Exploit prediction
0.70% chance of exploitation in the next 30 days, higher than 53% of all scored CVEs (FIRST EPSS, 2026-11-08).
Exploits and checks
- github.com https://github.com/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc referenced PoC, tagged "exploit" by a source, unverified
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| CNA | 4.0 | 8.2 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| CNA | 4.0 | 8.2 | CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
| NVD | 3.1 | 7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| hex | hackney | >=2.0.0, <4.0.1 |
4.0.1 |
Affected products
- benoitc hackney
Classification
References
-
github.com
/benoitc/hackney/commit/3d25f9fea26c90609de9d64366fedfe5065413bc
patch, web
-
github.com
/benoitc/hackney/security/advisories/GHSA-jq4m-q6p2-8gwc
vendor-advisory, related, exploit, web, patch, advisory
-
cna.erlef.org
/cves/CVE-2026-47077.html
related, web, patch, third-party-advisory
-
osv.dev
/vulnerability/EEF-CVE-2026-47077
related, web, patch, third-party-advisory
-
github.com
/ex-aws/ex_aws_sns/security/advisories/GHSA-8jgf-23q5-x7xx
web
-
nvd.nist.gov
/vuln/detail/CVE-2026-47077
advisory
-
github.com
/benoitc/hackney
package
-
hex.pm
/packages/hackney
package
Sources
- CVE List CVE-2026-47077
- GitHub Advisory GHSA-jq4m-q6p2-8gwc
- NVD CVE-2026-47077
- OSV EEF-CVE-2026-47077
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