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CVE-2012-1823

9.8, critical Known exploited

PHP-CGI Query String Parameter Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab) CISA KEV catalogue (opens in a new tab)
CVSS
9.8, critical critical CVSS v3.1
EPSS, next 30 days
100% higher than 99.9% of scored CVEs
Exploitation
Confirmed in the wild
Published
11 May 201214 years ago

Known exploited

CISA added this to the Known Exploited Vulnerabilities Catalog on 25 Mar 2022. US federal agencies had to remediate by 15 Apr 2022, a deadline that has passed.

Required action. Apply updates per vendor instructions.

Description

sapi/cgi/cgi_main.c in PHP before 5.3.12 and 5.4.x before 5.4.2, when configured as a CGI script (aka php-cgi), does not properly handle query strings that lack an = (equals sign) character, which allows remote attackers to execute arbitrary code by placing command-line options in the query string, related to lack of skipping a certain php_getopt for the 'd' case.

Details

Vendor
PHP and 7 more
Product
PHP
Weakness
CWE-77 (opens in a new tab)
Status
Analyzed
Updated
16 Jun 2026
Assigner
cret@cert.org

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

References 31

Exploit code 4

Patches and fixes 1

Advisories 15

7 more

Other references 11

3 more

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other PHP CVEs

Every PHP CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2019-11043 PHP FastCGI Process Manager (FPM) Buffer Overflow Vulnerability KEV EPSS 100% 9.8, critical
  • CVE-2016-10033 PHPMailer Command Injection Vulnerability KEV EPSS 100% 9.8, critical

Beyond this page

Is CVE-2012-1823 in your network?

This page tells you how dangerous CVE-2012-1823 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

CVE-2012-1823 is in the CISA catalogue of exploited vulnerabilities: attackers are already exploiting it.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2012-1823 comes with the devices to patch.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 16 Oct 2026, not the live upstream state.