Critical severity · published Oct 5, 2021
CVE-2021-41773
Path traversal and file disclosure vulnerability in Apache HTTP Server 2.4.49
RansomwareIn wildKEV
9.8
CVSS
100%
EPSS
Yes
On KEV
Description
A flaw was found in a change made to path normalization in Apache HTTP Server 2.4.49. An attacker could use a path traversal attack to map URLs to files outside the directories configured by Alias-like directives. If files outside of these directories are not protected by the usual default configuration "require all denied", these requests can succeed. If CGI scripts are also enabled for these aliased pathes, this could allow for remote code execution. This issue is known to be exploited in the wild. This issue only affects Apache 2.4.49 and not earlier versions. The fix in Apache HTTP Server 2.4.50 was found to be incomplete, see CVE-2021-42013.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)100.0% · higher than 100% of CVEs
Exploited in the wildYes
CISA KEVListed Nov 3, 2021
Federal remediation dueNov 17, 2021
Ransomware campaign useKnown
Affected products
Which versions
HS
HTTP Server · Apache
Apache HTTP Server 2.4 2.4.49 · source: vendor, NVD, KEV
CB
Cloud Backup · Netapp
All versions, or not specified · source: NVD
FE
Fedora · Fedoraproject
34; 35 · source: NVD
IE
Instantis Enterprisetrack · Oracle
17.1; 17.2; 17.3 · source: NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2021-41773
CVE.org
https://www.cve.org/CVERecord?id=CVE-2021-41773
CISA KEV catalogue
https://www.cisa.gov/known-exploited-vulnerabilities-catalog
x_refsource_MISC
https://httpd.apache.org/security/vulnerabilities_24.html
mailing-list
https://lists.apache.org/thread.html/r6abf5f2ba6f1aa8b1030f95367aaf17660c4e4c78cb2338aee18982f%40%3Cusers.httpd.apache.org%3E
mailing-list
https://lists.apache.org/thread.html/r98d704ed4377ed889d40479db79ed1ee2f43b2ebdd79ce84b042df45%40%3Cannounce.apache.org%3E
mailing-list
http://www.openwall.com/lists/oss-security/2021/10/05/2
mailing-list
http://www.openwall.com/lists/oss-security/2021/10/07/1
mailing-list
https://lists.apache.org/thread.html/r7c795cd45a3384d4d27e57618a215b0ed19cb6ca8eb070061ad5d837%40%3Cannounce.apache.org%3E
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