HTTP ServerWeb server / proxy · Apache
CVE-2019-10098
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 · uneditedIn Apache HTTP server 2.4.0 to 2.4.39, Redirects configured with mod_rewrite that were intended to be self-referential might be fooled by encoded newlines and redirect instead to an unexpected URL within the request URL.
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 · high confidenceApache HTTP Server 2.4.0 to 2.4.39 has a vulnerability in mod_rewrite where self-referential redirects (redirects intended to point back to the same host/path) can be bypassed using URL-encoded newlines (%0A). An attacker could craft a request containing encoded newlines to cause the server to redirect users to an attacker-controlled URL within the request, potentially enabling phishing or HTTP response splitting attacks.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
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
>= 2.4.0, <= 2.4.39CVSS 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
- Required
- Scope
- Changed
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check Apache HTTP Server versionRun 'httpd -v' or 'apache2 -v' to obtain the server version, or check the 'ServerTokens' and 'ServerVersion' directives in the configuration. On some systems, 'apachectl -V' also shows version information.Affected if The installed version is 2.4.0 through 2.4.39 inclusive.
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Verify mod_rewrite is loadedCheck the active Apache configuration for 'LoadModule rewrite_module' directives, or run 'httpd -M' or 'apachectl -M' to list loaded modules and look for 'rewrite_module' in the output.Affected if mod_rewrite is loaded and available for use in the configuration.
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Identify active RewriteRule directives performing redirectsSearch Apache configuration files (*.conf) for RewriteRule directives containing redirect flags such as [R], [R=301], [R=302], [R=303], [F], [L] (with external redirects), or [redirect=...]. Use commands like 'grep -r "RewriteRule.*\[R" /etc/apache2/' or review the main httpd.conf and included configuration files.Affected if Any RewriteRule with redirect flags (R, R=xxx) is configured, allowing outbound redirects from the server.
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Inspect redirect target patterns for URL validationExamine the RewriteRule patterns and conditions (RewriteCond) that define redirect targets. Look for whether the rule includes any validation or filtering of the redirect URL, such as checking for forbidden characters or using a strict pattern that excludes newline characters (%0A, %0D).Affected if Redirect rules lack input validation on the redirect target and do not explicitly reject or filter requests containing URL-encoded newline characters.
You are affected if Apache HTTP Server version is between 2.4.0 and 2.4.39 inclusive, mod_rewrite is loaded, and any RewriteRule with redirect flags is in use without validation that rejects %0A characters in the request.
Generated from the published advisory. Verify against your own configuration.
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.
From vendor dataUpgrade Apache HTTP Server to version 2.4.40 or later, or apply the vendor patch. Review existing mod_rewrite rules to ensure they properly validate redirect targets and reject requests containing newline characters.
Fix this in HTTP Server
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing3.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $3,088.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2019-10098 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2019-10098 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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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.
- 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