CVE-2021-28544 | Apache Subversion SVN authz protected copyfrom paths regression

Exp

Apache Subversion SVN authz protected copyfrom paths regression Subversion servers reveal 'copyfrom' paths that should be hidden according to configured path-based authorization (authz) rules. When a node has been copied from a protected location, users with access to the copy can see the 'copyfrom' path of the original. This also reveals the fact that the node was copied. Only the 'copyfrom' path is revealed; not its contents. Both httpd and svnserve servers are vulnerable.

Published: 2022-04-12 Last update: 2024-11-21 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2021-28544 is rated High Exploit Risk (63.9/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 2.70%). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +2.32% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

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

Public exploit references (Exploit-DB) for CVE-2021-28544

EDB-ID Source Kind Published Link
— nvd_ref exploit_tag Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2021-28544

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 2026-06-15 0.38% 2.70% +2.32%
2 2025-12-28 0.29% 0.38% +0.09%
3 2025-12-27 — 0.29% —

Full EPSS history (22 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2021-28544

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
4.3 3.1 MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/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:L)
A normal user session is enough; they don’t have to be admin.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:N)
Service keeps running; no real outage angle.
 2.8 1.4 [email protected]
3.5 2.0 LOW
AV:N/AC:M/Au:S/C:P/I:N/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:S)
A single authentication is required.
Confidentiality impact (C:P)
Partial confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:N)
No availability impact.
 6.8 2.9 [email protected]

Weakness enumeration for CVE-2021-28544

OS Trackers for CVE-2021-28544

vendor priority summary link
alpine medium CVE-2021-28544: 1 source package rows (subversion); 23 state rows across 8 repos (3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 7, open 16. https://security.alpinelinux.org/vuln/CVE-2021-28544
debian not yet assigned CVE-2021-28544 not yet assigned priority: Debian including 1 source packages (subversion), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2021-28544
redhat low — https://access.redhat.com/security/cve/CVE-2021-28544
suse medium CVE-2021-28544 severity moderate: SUSE including 57 source package names (libsvn_auth_gnome_keyring-1-0-1.10.6-150300.10.8.1, libsvn_auth_gnome_keyring-1-0-1.10.6-3.6.1, …), 222 product×package rows across 41 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (41 product lines)): Fixed 213, Known Not Affected 9. https://www.suse.com/security/cve/CVE-2021-28544/
ubuntu medium CVE-2021-28544 medium priority: Ubuntu including 1 source packages (subversion), 6 status rows across 6 suites (bionic, focal, impish, jammy, upstream, xenial): released 4, not-affected 2. https://ubuntu.com/security/CVE-2021-28544

Affected software / configurations for CVE-2021-28544

Vendor Product Version Raw CPE
apache subversion >= 1.10.0, <= 1.14.1 cpe:2.3:a:apache:subversion:*:*:*:*:*:*:*:*
debian debian_linux 10.0 cpe:2.3:o:debian:debian_linux:10.0:*:*:*:*:*:*:*
debian debian_linux 11.0 cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:*
fedoraproject fedora 35 cpe:2.3:o:fedoraproject:fedora:35:*:*:*:*:*:*:*
fedoraproject fedora 36 cpe:2.3:o:fedoraproject:fedora:36:*:*:*:*:*:*:*
apple macos >= 12.0, < 12.5 cpe:2.3:o:apple:macos:*:*:*:*:*:*:*:*

References for CVE-2021-28544

cvelogic Threat Intelligence