Vulnerability in Apache (CVE-2026-47321)
Summary
Vulnerability in Apache (CVE-2026-47321). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
The CompressionFilter class uses ZLib to deflate and inflate data sent and received. When we inflate incoming data, the filter does not control the resulting size, and create a buffer no matter what.
Some compressed data may have a compression ration greater than 1 thousand, leading to an exhaustion of the application memory, as we don't control the deflated size.
The fix adds such a control by allowing the application developer to provide a fixed size limit, which when reached throws an exception. It also allows the user to provide a compression ratio that should not be exceeded, protected the application from small inflated files that inflate in gigantic files, but with a grace limit for the resulting size (1Mb) to avoid false positive (like a very small file inflating with a high ratio, but resulting with a acceptable size, like a few thousands bytes)
For application using this feature, it is highly recommended to create the CompressionFilter and to pass the maximum limit as a forth constructor parameter, maxDecompressedSize:
public CompressionFilter(final boolean compressInbound, final boolean compressOutbound, final int compressionLevel, final int maxDecompressedSize)Optionally one can also provide a maxDecompressRatio fifth parameter, and a decompressRatioMinSize sixth parameter to allow small inflated files with a high compression ratio to still be accepted.
Here are the additional constructor:
public CompressionFilter(final boolean compressInbound, final boolean…
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-47321 has been found in Apache.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Apache CVE-2026-47321" on the vendor's site.
CVE-2026-47321 (Apache) — CWE-409 / CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (CWE-409) exists in Apache.
Check the vendor advisory for the affected versions of Apache.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'Apache' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'Apache' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
Apacheを grep し、稼働しているサービス・バージョンを把握する。 -
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2026-47321 mina
- Ubuntu UBUNTU-CVE-2026-47321 mina
References
- web lists.apache.org
- web openwall.com
- web nvd.nist.gov
- web github.com