How severe is CVE-2012-4388?

CVE-2012-4388 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2012-4388 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2012-4388?

CVE-2012-4388 primarily affects Php. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2012-4388?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2012-4388 published?

CVE-2012-4388 was published on 2012-09-07 and last updated on 2026-06-16.

CVE-2012-4388

CVE-2012-4388 is a medium-severity vulnerability in Php with a CVSS 2.0 base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-20.

Key facts

Severity: Medium (CVSS 2.0 base score 4.3)
EPSS exploit prediction: 4% (90th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Php
Published: 2012-09-07
Last modified: 2026-06-16

Description

The sapi_header_op function in main/SAPI.c in PHP 5.4.0RC2 through 5.4.0 does not properly determine a pointer during checks for %0D sequences (aka carriage return characters), which allows remote attackers to bypass an HTTP response-splitting protection mechanism via a crafted URL, related to improper interaction between the PHP header function and certain browsers, as demonstrated by Internet Explorer and Google Chrome. NOTE: this vulnerability exists because of an incorrect fix for CVE-2011-1398.

Frequently asked questions

What is CVE-2012-4388?: The sapi_header_op function in main/SAPI.c in PHP 5.4.0RC2 through 5.4.0 does not properly determine a pointer during checks for %0D sequences (aka carriage return characters), which allows remote attackers to bypass an HTTP response-splitting protection mechanism via a crafted URL, related to improper interaction between the PHP header function and certain browsers, as demonstrated by Internet Explorer and Google Chrome. NOTE: this vulnerability exists because of an incorrect fix for CVE-2011-1398.
How severe is CVE-2012-4388?: CVE-2012-4388 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2012-4388 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (90th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2012-4388?: CVE-2012-4388 primarily affects Php. In total, 8 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2012-4388?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2012-4388 published?: CVE-2012-4388 was published on 2012-09-07 and last updated on 2026-06-16.

References

Affected products (8)

cpe:2.3:a:php:php:*:*:*:*:*:*:*:*
cpe:2.3:a:php:php:5.4.0:rc2:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:8.04:*:*:*:-:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:10.04:*:*:*:-:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:11.04:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:11.10:*:*:*:*:*:*:*
cpe:2.3:o:canonical:ubuntu_linux:12.04:*:*:*:-:*:*:*
cpe:2.3:o:debian:debian_linux:6.0:*:*:*:*:*:*:*

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Threat intelligence

Threat-intel indicators referencing this CVE:

221.161.235.168 (ipv4-addr)
103.20.122.54 (ipv4-addr)
220.88.220.59 (ipv4-addr)
211.253.10.61 (ipv4-addr)
121.78.158.30 (ipv4-addr)
121.132.27.238 (ipv4-addr)
179.125.175.74 (ipv4-addr)
103.84.236.242 (ipv4-addr)