Vulnerability details

CVE-2026-97200

benoitc hackney

Unbounded response body buffering and decompression in hackney

CVSS 4.0

8.2High

Official description

Allocation of Resources Without Limits or Throttling vulnerability in hackney_conn in benoitc hackney allows a malicious HTTP server to exhaust client memory via an oversized or highly compressed response body. hackney:request/5 and hackney:body/1 return the whole response body, and nothing bounds how much the connection process buffers. Any server the client requests can trigger it. hackney_conn:read_full_body/2 and the HTTP/2 and HTTP/3 accumulators append every chunk until the body ends. With {auto_decompress, true} the buffered body is then inflated in one step with zlib:gunzip/1 or zlib:inflate/2, which return the whole output at once. This issue affects hackney: from 2.0.0-beta.1 before 4.9.0.

CVSS scores

Score	Version	Source	Vector
8.2High	4.0	CVEProject cvelistV5 (CNA) (EEF)	`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`

Affected products

Vendor	Product	Versions	Source
benoitc	hackney	2.0.0-beta.1 ≤ v < 4.9.0	CVEProject cvelistV5 (CNA)
benoitc	hackney	dc41b79339ca0c41e16d3f2dd17172bc2de855d6 ≤ v < 493e8bf83a391548e5101792276ab3fc428fa76c	CVEProject cvelistV5 (CNA)

References and advisories

https://github.com/benoitc/hackney/releases/tag/4.9.0 vendor-advisoryrelated
https://cna.erlef.org/cves/CVE-2026-97200.html related
https://osv.dev/vulnerability/EEF-CVE-2026-97200 related
https://github.com/benoitc/hackney/pull/980 related
https://github.com/benoitc/hackney/commit/dc41b79339ca0c41e16d3f2dd17172bc2de855d6 related
https://github.com/benoitc/hackney/commit/493e8bf83a391548e5101792276ab3fc428fa76c patch

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Details

Published: 2026-10-26
Last updated: 2026-10-26
State: Published
Assigner (CNA): EEF

Exploit prediction (EPSS)

0.56%

Probability of exploitation in 30 days

47%

Percentile (among all CVEs)

SSVC assessment (CISA)

Automatable: Yes
Exploitation: None
Technical impact: Partial

Weaknesses (CWE)

CWE-409
Improper Handling of Highly Compressed Data (Data Amplification)
CWE-770
Allocation of Resources Without Limits or Throttling