VulnerabilityAnalyzed
CVE-2021-39275
ap_escape_quotes() may write beyond the end of a buffer when given malicious input.
CRITICAL 9.8EPSS 39.4%
Does this matter?
EPSS puts the probability of exploitation in the next 30 days at 39.4%, higher than 99% of all known CVEs. Patch or mitigate before the next change window.
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.
- CVSS 3.1
- 9.8 CRITICALCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 39.40% probability · 99th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-787
- Affected
- apache/http server · fedoraproject/fedora · debian/debian linux · netapp/cloud backup · netapp/clustered data ontap · netapp/storagegrid · oracle/http server · oracle/instantis enterprisetrack · oracle/zfs storage appliance kit · siemens/sinec nms · siemens/sinema server
- Source
- security@apache.org
EPSS 39.4% since 3 November 2026; no change recorded yet. The dashed line is the ten per cent mark our analysts treat as “patch before the next change window”. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
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
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.