Answer in brief
CVE-2026-85721 records a High severity (CVSS 7.5) vulnerability in AsyncHttpClient: Unbounded HTTP/1.1 response decompression enables a decompression-bomb denial of service. The current sources do not mark it as known exploited. The current feed maps AsyncHttpClient/async-http-client (generic), org.asynchttpclient:async-http-client (maven), org.asynchttpclient:async-http-client (maven), org.asynchttpclient:async-http-client (maven) and additional mapped packages. Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 7.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps AsyncHttpClient/async-http-client (generic), org.asynchttpclient:async-http-client (maven), org.asynchttpclient:async-http-client (maven), org.asynchttpclient:async-http-client (maven) and additional mapped packages. Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| AsyncHttpClient/async-http-clientgeneric | >=2.0.0 <2.16.1 || >=3.0.0 <3.0.12 | 2.16.1, 3.0.12 |
| org.asynchttpclient:async-http-clientmaven | >=3.0.0,<=3.0.11 | 3.0.12 |
| org.asynchttpclient:async-http-clientmaven | >=2.0.0,<=2.16.0 | 2.16.1 |
| org.asynchttpclient:async-http-clientmaven | >=3.0.0 <3.0.12 | 3.0.12 |
| org.asynchttpclient:async-http-clientmaven | >=2.0.0 <2.16.1 | 2.16.1 |
Published upstream
Sep 17, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Sep 30, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Sep 17, 2026
The AsyncHttpClient (AHC) library allows Java applications to easily execute HTTP requests and asynchronously process HTTP responses. From 2.0.0 until 2.16.1 and 3.0.12, automatic response decompression on the HTTP/1.1 path uses ChannelManager.newHttpContentDecompressor() to install Http1ContentDecompressor without a cumulative output-size limit. A hostile or compromised server, or an attacker who can alter a response in transit, can send a small gzip, deflate, or snappy response that expands across chunks until the client exhausts its heap and raises OutOfMemoryError; brotli and zstd are also affected when their optional codecs are present. In versions 3.0.8 through 3.0.10, the HTTP/2 decompressor is also unbounded, so switching protocols does not mitigate the issue on those releases. A limit applied to each decode call is insufficient because the response can be delivered as many small chunks, so the fixed implementation tracks total decompressed bytes for the whole response. This issue is fixed in versions 2.16.1 and 3.0.12.
Quoted source text, attributed separately from HOL analysis.