CVE-2026-84382: HTTPX2: Streaming response decompression does not bound peak memory (decompression amplification)
Vulnerability summary
CVE-2026-84382 is a high (CVSS 7.5) vulnerability in pydantic httpx2. EPSS estimates a 0.63% chance of exploitation in the next 30 days, higher than 50.2% of scored vulnerabilities.
Severe, CVSS 7.5 (CVE.org); no exploitation reported by the 5 checked sources; EPSS 1% (FIRST, 03-11-2026)
Source freshness unavailable
How is this decided?Timeline
- 02-09-2026PublishedVulnerability first disclosed.
- 03-09-2026Last modifiedVulnerability information updated.
Description
HTTPX2 is a next generation HTTP client for Python. Prior to 2.12.0, the HTTPX2 content decoders in src/httpx2/httpx2/_decoders.py fully inflate each gzip, deflate, br, or zstd network chunk before iter_bytes() or aiter_bytes() yields bounded pieces to the application. A 64 KiB compressed chunk can expand to approximately 64 MiB in one intermediate allocation, so an attacker-controlled or compromised server can cause severe memory pressure or out-of-memory process termination even when the application streams the response. This issue is fixed in version 2.12.0.
CVSS metrics
7 scores · 7 sources · 1 version- OSV · PypiEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · WolfiEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · ChainguardEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVDNIST7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- OSV · UbuntuEcosystem advisory · calculated7.5HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
0.63%
Chance of exploitation in the next 30 days
Percentile
50%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.63% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Chainguard5 products
- lmcache-cuda-13.0< 0.5.3-r2
- py3.10-httpx2< 2.12.0-r0
- py3.11-httpx2< 2.12.0-r0
- py3.12-httpx2< 2.12.0-r0
- py3.13-httpx2< 2.12.0-r0
Wolfi4 products
- py3.10-httpx2< 2.12.0-r0
- py3.11-httpx2< 2.12.0-r0
- py3.12-httpx2< 2.12.0-r0
- py3.13-httpx2< 2.12.0-r0
Debian1 product
- python-httpx2< 2.12.0-1
Pydantic1 product
- httpx2< 2.12.0
PyPI1 product
- httpx2< 2.12.0
Ubuntu1 product
- python-httpx2All versions (No fix recorded)
6 vendors · 13 products
References
12 links- github.com/pydantic/httpx2/security/advisories/GHSA-8xx6-hgc6-gc2mX Refsource CONFIRMWEBAdvisoryREPORT
- github.com/pydantic/httpx2/commit/4fd0c70a3f207c618b145934792f791bccfb39f8X Refsource MISCWEBFIXREPORT
- github.com/pydantic/httpx2PACKAGE
- pypi.org/project/httpx2PACKAGE
