CVE-2021-39275
ap_escape_quotes buffer overflow
CRITICAL
9.8
CVSS Score
Published: September 16, 2021 at 02:40 PM UTC
Updated: June 17, 2026 at 04:03 AM UTC
11 products affected across 6 vendorsDebian LinuxFedoraHTTP Server
Using Apache HTTP Server by Apache Software Foundation?
Get instant alerts when new vulnerabilities affect Apache HTTP Server - before attackers find them.
Real-time alertsTrack your software stackFree plan available
Severity
CRITICAL9.8
Exploit prediction
EPSS 39%
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.
Affected
Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.
Affected range stops below 2.4.49, so it looks safe — our inference, not a vendor statement
Debian Linux· Debiandrupal
95%Cloud Backup· NetAppdrupal
95%All versions
All versions
All versions
Remediation
No guide yetNo remediation guidance has been written for this CVE yet. What the record does show:
Patch and advisory references
- https://httpd.apache.org/security/vulnerabilities_24.html
- https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3E
- https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3E
- https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3E
- https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3E
References (15)
x_refsource_CONFIRMThird Party Advisory
Source: [email protected]
https://cert-portal.siemens.com/productcert/pdf/ssa-685781.pdfx_refsource_MISCRelease NotesVendor Advisory
Source: [email protected]
https://httpd.apache.org/security/vulnerabilities_24.htmlMailing Listx_refsource_MLISTPatch
Source: [email protected]
https://lists.apache.org/thread.html/r3925e167d5eb1c75def3750c155d753064e1d34a143028bb32910432%40%3Cusers.httpd.apache.org%3EMailing Listx_refsource_MLISTPatch
Source: [email protected]
https://lists.apache.org/thread.html/r61fdbfc26ab170f4e6492ef3bd5197c20b862ce156e9d5a54d4b899c%40%3Cusers.httpd.apache.org%3EMailing Listx_refsource_MLISTPatch
Source: [email protected]
https://lists.apache.org/thread.html/r82838efc5fa6fc4c73986399c9b71573589f78b31846aff5bd9b1697%40%3Cusers.httpd.apache.org%3EMailing Listx_refsource_MLISTPatch
Source: [email protected]
https://lists.apache.org/thread.html/r82c077663f9759c7df5a6656f925b3ee4f55fcd33c889ba7cd687029%40%3Cusers.httpd.apache.org%3EMailing Listx_refsource_MLISTThird Party Advisory
Source: [email protected]
https://lists.debian.org/debian-lts-announce/2021/10/msg00001.htmlVendor Advisoryx_refsource_FEDORAThird Party Advisory
Source: [email protected]
https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/SPBR6WUYBJNACHKE65SPL7TJOHX7RHWD/CVSS
- Attack Vector
- NETWORK
- Complexity
- LOW
- Privileges
- NONE
- User Interaction
- NONE
- Scope
- UNCHANGED
- Confidentiality
- HIGH
- Integrity
- HIGH
- Availability
- HIGH
Vector?
Quick Info
StatusANALYZED
CWE
CWE-787
Get alerted
Stop reading CVE feeds looking for your own stack
Track the products you run and VulnTracker tells you when a new CVE affects them — with what is known about fixing it, and nothing about the rest.
Free plan, no card