Vulnerability in Apache HTTP Server (CVE-2021-26690)

Summary

Vulnerability in Apache HTTP Server (CVE-2021-26690). Risk of unauthorized operations or information disclosure. Exploitable via Cookie header.

Original description

The description as published by the source.

Apache HTTP Server versions 2.4.0 to 2.4.46 A specially crafted Cookie header handled by mod_session can cause a NULL pointer dereference and crash, leading to a possible Denial Of Service

Source: OSV.dev (Open Source Vulnerabilities) NVD OSV

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-2021-26690 has been found in Apache HTTP Server.
Attackers can target a specific entry point like Cookie header over the network to misuse the product.
Risk of unauthorized operations or information disclosure.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Apache HTTP Server CVE-2021-26690" on the vendor's site.

CVE-2021-26690 (Apache HTTP Server)
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Attack surface: Cookie header
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.

❓ What is the problem

A vulnerability (unclassified) exists in Apache HTTP Server. Attackers reach the vulnerable code path via Cookie header without authentication.

📍 Affected scope

Check the vendor advisory for the affected versions of Apache HTTP Server. Attack surface: Cookie header.

🔥 Severity

Severity: ?. Risk of unauthorized operations or information disclosure.

🔧 How to fix

Update to the patched release per vendor advisory.

🛡️ Workaround

Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.

🔍 Detection

Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.

Response actions

Concrete steps and command examples for SOC/SRE teams to execute in order

1
Identify exposure identify
```
Audit SBOM/dependencies for affected components.
```
資産台帳・SBOM・依存マニフェストで Apache HTTP Server を使っているサービスとバージョンを洗い出す。
2
Post-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。

Affected packages

Bitnami apache

[{"type":"SEMVER","events":[{"introduced":"2.4.0"},{"fixed":"2.4.47"}]}]

Fix status by distribution

Fixed packages published by each distribution for this CVE

Alpine Linux ALPINE-CVE-2021-26690 apache2 Fixed in: 2.4.48-r0
Debian DEBIAN-CVE-2021-26690 apache2 Fixed in: 2.4.46-6