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Vulnerability details: VCID-1deu-fvex-vkhw
Vulnerability ID VCID-1deu-fvex-vkhw
Aliases CVE-2021-26690
Summary Apache HTTP Server versions 2.4.0 to 2.4.46 A specially crafted Cookie header handled by mod_session can cause a NULL pointer dereference and crash, leading to a possible Denial Of Service
Status Published
Exploitability 0.5
Weighted Severity 6.8
Risk 3.4
Affected and Fixed Packages Package Details
Weaknesses (1)
CWE-476 NULL Pointer Dereference
System Score Found at
cvssv3 7.5 https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-26690.json
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.68374 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
epss 0.75025 https://api.first.org/data/v1/epss?cve=CVE-2021-26690
cvssv3.1 8.1 https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
apache_httpd low https://httpd.apache.org/security/json/CVE-2021-26690.json
cvssv2 5.0 https://nvd.nist.gov/vuln/detail/CVE-2021-26690
cvssv3.1 7.5 https://nvd.nist.gov/vuln/detail/CVE-2021-26690
archlinux Medium https://security.archlinux.org/AVG-2053
Reference id Reference type URL
https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-26690.json
https://api.first.org/data/v1/epss?cve=CVE-2021-26690
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-35452
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-26690
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-26691
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-30641
https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2021-31618
https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
https://lists.apache.org/thread.html/r7f2b70b621651548f4b6f027552f1dd91705d7111bb5d15cda0a68dd%40%3Cdev.httpd.apache.org%3E
https://lists.apache.org/thread.html/rae406c1d19c0dfd3103c96923dadac2af1cd0bad6905ab1ede153865%40%3Cannounce.httpd.apache.org%3E
https://lists.apache.org/thread.html/re026d3da9d7824bd93b9f871c0fdda978d960c7e62d8c43cba8d0bf3%40%3Ccvs.httpd.apache.org%3E
https://security.netapp.com/advisory/ntap-20210702-0001/
https://www.oracle.com/security-alerts/cpuoct2021.html
http://www.openwall.com/lists/oss-security/2021/06/10/6
1966729 https://bugzilla.redhat.com/show_bug.cgi?id=1966729
AVG-2053 https://security.archlinux.org/AVG-2053
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*
cpe:2.3:a:oracle:enterprise_manager_ops_center:12.4.0.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:enterprise_manager_ops_center:12.4.0.0:*:*:*:*:*:*:*
cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:instantis_enterprisetrack:17.1:*:*:*:*:*:*:*
cpe:2.3:a:oracle:instantis_enterprisetrack:17.2:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:instantis_enterprisetrack:17.2:*:*:*:*:*:*:*
cpe:2.3:a:oracle:instantis_enterprisetrack:17.3:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:instantis_enterprisetrack:17.3:*:*:*:*:*:*:*
cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:oracle:zfs_storage_appliance_kit:8.8:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
CVE-2021-26690 https://httpd.apache.org/security/json/CVE-2021-26690.json
CVE-2021-26690 https://nvd.nist.gov/vuln/detail/CVE-2021-26690
RHSA-2021:4257 https://access.redhat.com/errata/RHSA-2021:4257
RHSA-2021:4613 https://access.redhat.com/errata/RHSA-2021:4613
RHSA-2021:4614 https://access.redhat.com/errata/RHSA-2021:4614
USN-4994-1 https://usn.ubuntu.com/4994-1/
USN-4994-2 https://usn.ubuntu.com/4994-2/
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://access.redhat.com/hydra/rest/securitydata/cve/CVE-2021-26690.json
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H Found at https://ftp.suse.com/pub/projects/security/yaml/suse-cvss-scores.yaml
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: AV:N/AC:L/Au:N/C:N/I:N/A:P Found at https://nvd.nist.gov/vuln/detail/CVE-2021-26690
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Found at https://nvd.nist.gov/vuln/detail/CVE-2021-26690
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.98531
EPSS Score 0.68374
Published At July 31, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-31T08:29:08.386004+00:00 Apache HTTPD Importer Import https://httpd.apache.org/security/json/CVE-2021-26690.json 37.0.0