CVE-2021-3524

A flaw was found in the Red Hat Ceph Storage RadosGW (Ceph Object Gateway) in versions before 14.2.21. The vulnerability is related to the injection of HTTP headers via a CORS ExposeHeader tag. The newline character in the ExposeHeader tag in the CORS configuration file generates a header injection in the response when the CORS request is made. In addition, the prior bug fix for CVE-2020-10753 did not account for the use of \r as a header separator, thus a new flaw has been created.

Published: 2021-05-17 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-3524 is rated Moderate Risk (52.8/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.93%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2021-3524

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-01-17 0.58% 0.93% +0.35%
2 2025-12-28 0.49% 0.58% +0.09%
3 2025-12-27 — 0.49% —

Full EPSS history (30 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-3524

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
6.5 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:H/A:N Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:R)
A real person has to do something—click, install, enable—otherwise it doesn’t land.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:P/A:N Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:P)
Partial integrity impact.
Availability impact (A:N)
No availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2021-3524

OS Trackers for CVE-2021-3524

vendor priority summary link
alpine medium CVE-2021-3524: 2 source package rows (ceph, ceph16); 7 state rows across 3 repos (3.17-community, 3.18-community, edge-community); fixed 4, open 3. https://security.alpinelinux.org/vuln/CVE-2021-3524
debian not yet assigned CVE-2021-3524 not yet assigned priority: Debian including 1 source packages (ceph), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-3524
redhat medium — https://access.redhat.com/security/cve/CVE-2021-3524
suse medium CVE-2021-3524 severity moderate: SUSE including 364 source package names (0.45.0.8.14.1:librados2-15.2.12.83+g528da226523-3.25.1, 0.45.0.8.14.1:librbd1-15.2.12.83+g528da226523-3.25.1, …), 581 product×package rows across 45 product lines (Container caasp/v4/hyperkube, Container ses/6/cephcsi/cephcsi, … (45 product lines)): Fixed 567, Known Not Affected 14. https://www.suse.com/security/cve/CVE-2021-3524/
ubuntu medium CVE-2021-3524 medium priority: Ubuntu including 1 source packages (ceph), 15 status rows across 15 suites (bionic, focal, groovy, hirsute, impish, jammy, kinetic, lunar, mantic, noble, oracular, plucky, trusty, upstream, xenial): released 14, not-affected 1. https://ubuntu.com/security/CVE-2021-3524

Affected software / configurations for CVE-2021-3524

Vendor Product Version Raw CPE
redhat ceph < 14.2.21 cpe:2.3:a:redhat:ceph:*:*:*:*:*:*:*:*
redhat ceph_storage 4.0 cpe:2.3:a:redhat:ceph_storage:4.0:*:*:*:*:*:*:*
fedoraproject fedora 32 cpe:2.3:o:fedoraproject:fedora:32:*:*:*:*:*:*:*
fedoraproject fedora 33 cpe:2.3:o:fedoraproject:fedora:33:*:*:*:*:*:*:*
fedoraproject fedora 34 cpe:2.3:o:fedoraproject:fedora:34:*:*:*:*:*:*:*
debian debian_linux 9.0 cpe:2.3:o:debian:debian_linux:9.0:*:*:*:*:*:*:*

References for CVE-2021-3524

cvelogic Threat Intelligence