ViewVC, a browser interface for CVS and Subversion version control repositories, as a cross-site scripting vulnerability that affects versions prior to 1.2.2 and 1.1.29. The impact of this vulnerability is mitigated by the need for an attacker to have commit privileges to a Subversion repository exposed by an otherwise trusted ViewVC instance. The attack vector involves files with unsafe names (names that, when embedded into an HTML stream, would cause the browser to run unwanted code), which themselves can be challenging to create. Users should update to at least version 1.2.2 (if they are using a 1.2.x version of ViewVC) or 1.1.29 (if they are using a 1.1.x version). ViewVC 1.0.x is no longer supported, so users of that release lineage should implement a workaround. Users can edit their ViewVC EZT view templates to manually HTML-escape changed paths during rendering. Locate in your template set's `revision.ezt` file references to those changed paths, and wrap them with `[format "html"]` and `[end]`. For most users, that means that references to `[changes.path]` will become `[format "html"][changes.path][end]`. (This workaround should be reverted after upgrading to a patched version of ViewVC, else changed path names will be doubly escaped.)
Conclusion & alert: CVE-2023-22456 is rated Moderate Risk (47.6/100): CVSS Medium severity, with medium exploitation likelihood (EPSS 0.53%). Mandatory action: Review affected assets and schedule remediation.
Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.
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 | 2026-04-23 | 0.84% | 0.53% | -0.32% |
| 2 | 2026-03-12 | 0.89% | 0.84% | -0.04% |
| 3 | 2026-01-30 | — | 0.89% | — |
Full EPSS history (13 records total)
CVSS metrics for this CVE.
| Base score | Version | Severity | Vector | Exploitability | Impact | Score source |
|---|---|---|---|---|---|---|
| 6.1 | 3.1 | MEDIUM |
|
2.8 | 2.7 | [email protected] |
| 6.1 | 3.1 | MEDIUM |
|
2.8 | 2.7 | [email protected] |
| vendor | priority | summary | link |
|---|---|---|---|
suse
|
medium | — | https://www.suse.com/security/cve/CVE-2023-22456/ |
ubuntu
|
medium | CVE-2023-22456 medium priority: Ubuntu including 1 source packages (viewvc), 7 status rows across 7 suites (bionic, focal, jammy, kinetic, trusty, upstream, xenial): DNE 3, needs-triage 3, ignored 1. | https://ubuntu.com/security/CVE-2023-22456 |
| URL | Tags |
|---|---|
| https://github.com/viewvc/viewvc/issues/311 | Issue Tracking Third Party Advisory |
| https://github.com/viewvc/viewvc/releases/tag/1.1.29 | Patch Third Party Advisory |
| https://github.com/viewvc/viewvc/releases/tag/1.2.2 | Patch Third Party Advisory |
| https://github.com/viewvc/viewvc/security/advisories/GHSA-j4mx-f97j-gc5g | Third Party Advisory |