PHPApplication
CVE-2025-1861
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 PHP from 8.1.* before 8.1.32, from 8.2.* before 8.2.28, from 8.3.* before 8.3.19, from 8.4.* before 8.4.5, when parsing HTTP redirect in the response to an HTTP request, there is currently limit on the location value size caused by limited size of the location buffer to 1024. However as per RFC9110, the limit is recommended to be 8000. This may lead to incorrect URL truncation and redirecting to a wrong location.
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 confidenceIn PHP versions 8.1 before 8.1.32, 8.2 before 8.2.28, 8.3 before 8.3.19, and 8.4 before 8.4.5, the HTTP redirect handling uses a fixed 1024-byte buffer for the Location header value. RFC 9110 recommends supporting up to 8000 bytes. When a redirect Location exceeds 1024 bytes, it gets incorrectly truncated, potentially redirecting users to a wrong/malicious URL.
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
PHPApplication
>= 8.1.0, < 8.1.31>= 8.2.0, < 8.2.26>= 8.3.0, < 8.3.14>= 8.4.0, < 8.4.5= 9CVSS 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
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
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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Identify installed PHP versionRun `php -v` on the command line or use `phpinfo()` in a script to retrieve the PHP version numberAffected if The version is >= 8.1.0 and < 8.1.31, OR >= 8.2.0 and < 8.2.26, OR >= 8.3.0 and < 8.3.14, OR >= 8.4.0 and < 8.4.5
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Determine if PHP performs HTTP redirectsSearch source code for calls to header() with 'Location:' or http_redirect() function, or inspect web server logs for 3xx responsesAffected if The application uses PHP to perform HTTP redirects via the Location header and the target URLs can exceed 1024 characters
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Test for URL truncation behaviorCreate a test script that issues a redirect with a Location header longer than 1024 bytes and inspect the received header or final destination URLAffected if The redirect URL is truncated at or around 1024 characters, causing the user to be redirected to an incomplete or attacker-controlled URL
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Check if NetApp ONTAP is in useIdentify if the environment runs NetApp ONTAP version 9, which bundles the affected PHP versionAffected if NetApp ONTAP version 9 is deployed and uses the bundled PHP version falling within the affected ranges
The environment is affected if PHP version falls within the vulnerable ranges AND the application performs HTTP redirects that could involve Location headers longer than 1024 characters, causing truncation and potential redirection to attacker-controlled domains.
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.
dbcve · scoped8.1.318.2.268.3.14
Upgrade PHP to version 8.1.32, 8.2.28, 8.3.19, 8.4.5 or later, which increases the Location buffer to comply with RFC 9110.
Upgrade to PHP 8.1.32+, 8.2.28+, 8.3.19+, or 8.4.5+ depending on your current branch
- Identify the currently installed PHP version using 'php -v' or 'php --version'
- Determine which PHP branch you are using (8.1.x, 8.2.x, 8.3.x, or 8.4.x)
- For systems using package managers, update to the latest patch version: On Debian/Ubuntu: 'sudo apt update && sudo apt install php*' or 'sudo apt install php8.x' (replace x with your branch)
- On Red Hat/CentOS/Fedora: 'sudo dnf update php-*' or 'sudo yum update php-*'
- On Alpine: 'apk update && apk upgrade php*'
- For Windows, download the fixed version from windows.php.net/download/
- After upgrade, verify the fix by checking 'php -v' shows version 8.1.32+, 8.2.28+, 8.3.19+, or 8.4.5+
- Test that HTTP redirect handling works correctly with longer Location headers
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in PHP
Scoped from the published advisory
- Consultation1.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,144.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2025-1861 — 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-2025-1861 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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- 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
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