dbcve.org
HTTP ServerWeb server / proxy · Apache

CVE-2021-36160

HIGH · 7.5 CVSS v3.1 Published 2021-09-16
Fix available
A fix is available. Upgrade to 2.4.49 or later.
See remediation →
84/100
Remediation priority · High
High EPSS Remotely reachable No privileges Zero-click Patch available

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
A carefully crafted request uri-path can cause mod_proxy_uwsgi to read above the allocated memory and crash (DoS). This issue affects Apache HTTP Server versions 2.4.30 to 2.4.48 (inclusive).

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis
How this class of weakness works · CWE-125

The code reads past the end (or before the start) of a buffer, returning memory that was never meant to be exposed. Attackers use it to leak secrets like keys or to defeat memory-protection defences. Remediation is validating indices and lengths before every read.

General guidance for the out-of-bounds read class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
HTTP ServerWeb server / proxy
Affected:>= 2.4.30, < 2.4.49
FedoraOperating system
Affected:= 34= 35
Debian LinuxOperating system
Affected:= 9.0= 10.0= 11.0
HTTP ServerWeb server / proxy
Affected:= 12.2.1.3.0= 12.2.1.4.0
Cloud BackupApplication
Affected:all versions
Clustered Data OntapApplication
Affected:all versions
StoragegridApplication
Affected:all versions
Communications Cloud Native Core Network Function Cloud Native EnvironmentApplication
Affected:= 1.10.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 2.4.49 or later
Fixed in 2.4.49
Vendor patch lists.apache.org →
Recommended fix High confidence

Apache HTTP Server 2.4.49 or later

  1. Check current Apache HTTP Server version using 'httpd -v' or 'apache2 -v'
  2. Stop the Apache HTTP Server service
  3. Backup the current Apache configuration directory (e.g., /etc/httpd or /etc/apache2)
  4. Upgrade Apache HTTP Server to version 2.4.49 or later using the package manager (e.g., 'dnf update httpd' on Fedora, 'apt-get update && apt-get upgrade apache2' on Debian, or 'yum update httpd' on RHEL-based systems)
  5. Verify the installed version is 2.4.49 or later using 'httpd -v' or 'apache2 -v'
  6. Start the Apache HTTP Server service
  7. Test that the mod_proxy_uwsgi module loads correctly and the server responds
Caveat Minor - ensure any custom mod_proxy_uwsgi configurations are compatible with the new version; review release notes for any behavioral changes between 2.4.30-2.4.48 and 2.4.49+

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $3,200. Get the upgrade done

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2021-36160 in production — separate from our analysis above.

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here
  • Verified mitigations, workarounds, and config changes
  • Version or environment caveats, and links to real fixes
  • No weaponised exploit code, or anything meant to cause harm
  • No spam, self-promotion, credentials, or personal data