CVE-2021-39275

Name: CVE-2021-39275
Creator: NVD / NIST
Published: 2021-09-16T15:15:07.58+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

CRITICALCVSS 9.8/10EPSS 36.34%

Last modified Jun 17, 2026

CVE-2021-39275 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. ap_escape_quotes() may write beyond the end of a buffer when given malicious input. No included modules pass untrusted data to these functions, but third-party / external modules may. EPSS estimates a 36.34% chance of exploitation in the next 30 days.

Description

ap_escape_quotes() may write beyond the end of a buffer when given malicious input. No included modules pass untrusted data to these functions, but third-party / external modules may. This issue affects Apache HTTP Server 2.4.48 and earlier.

Metrics

CVSS 3.1

9.8/10

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

EPSS Probability

36.34%

98.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

CWE-787

Affected Software

Vendor	Product	Versions
Apache	Http Server	< 2.4.49
Fedoraproject	Fedora	34
Fedoraproject	Fedora	35
Debian	Debian Linux	9.0
Debian	Debian Linux	10.0
Debian	Debian Linux	11.0
Netapp	Cloud Backup	All versions
Netapp	Clustered Data Ontap	All versions
Netapp	Storagegrid	All versions
Oracle	Http Server	12.2.1.3.0
Oracle	Http Server	12.2.1.4.0
Oracle	Instantis Enterprisetrack	17.1
Oracle	Instantis Enterprisetrack	17.2
Oracle	Instantis Enterprisetrack	17.3
Oracle	Zfs Storage Appliance Kit	8.8
Siemens	Sinec Nms	All versions
Siemens	Sinema Server	14.0

References

https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdfThird Party Advisory
https://httpd.apache.org/security/vulnerabilities_24.htmlRelease Notes, Vendor Advisory
https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3EPatch
https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3EPatch
https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3EPatch
https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3EPatch
https://lists.debian.org/debian-lts-announce/2021/10/msg00001.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/Third Party Advisory
https://security.gentoo.org/glsa/202208-20Third Party Advisory
https://security.netapp.com/advisory/ntap-20211008-0004/Third Party Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQThird Party Advisory
https://www.debian.org/security/2021/dsa-4982Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.htmlPatch, Third Party Advisory
https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdfThird Party Advisory
https://httpd.apache.org/security/vulnerabilities_24.htmlRelease Notes, Vendor Advisory
https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3EPatch
https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3EPatch
https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3EPatch
https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3EPatch
https://lists.debian.org/debian-lts-announce/2021/10/msg00001.htmlMailing List, Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/Third Party Advisory
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/ZNCYSR3BXT36FFF4XTCPL3HDQK4VP45R/Third Party Advisory
https://security.gentoo.org/glsa/202208-20Third Party Advisory
https://security.netapp.com/advisory/ntap-20211008-0004/Third Party Advisory
https://tools.cisco.com/security/center/content/CiscoSecurityAdvisory/cisco-sa-apache-httpd-2.4.49-VWL69sWQThird Party Advisory
https://www.debian.org/security/2021/dsa-4982Third Party Advisory
https://www.oracle.com/security-alerts/cpuapr2022.htmlPatch, Third Party Advisory
https://www.oracle.com/security-alerts/cpujan2022.htmlPatch, Third Party Advisory

Timeline

Published: Sep 16, 2021
Last Modified: Jun 17, 2026
Status: Analyzed

Frequently Asked Questions

What is CVE-2021-39275?

How severe is CVE-2021-39275?

CVE-2021-39275 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 36.34% probability of exploitation in the next 30 days.

How do I fix CVE-2021-39275?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-39275?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST