BREW-TOPYDO-CVE-2026-103022 (GHSA-CP25-J9X5-P5XM)

Vulnerability from osv_homebrew – Published: 2026-11-10 11:04 – Updated: 2026-11-10 11:04 – Source website
VLAI
Summary
Urwid: handle_short_request() crashes on non-ASCII POST body (UnicodeEncodeError DoS)
Details

Summary

The handle_short_request() function in urwid/display/web.py raises an unhandled UnicodeEncodeError when processing a POST request body containing non-ASCII bytes. The function reads POST input and encodes it to ASCII before writing to a named pipe. Any byte value above 0x7F causes the CGI process to exit with an unhandled exception, returning an HTTP 500 error to the client. Additionally, a file descriptor opened earlier in the same function is not closed before the exception propagates, causing a file descriptor leak for the lifetime of the CGI process.

A second instance of missing exception handling exists in the polling update path, where non-UTF-8 socket output causes an unhandled UnicodeDecodeError.

Impact

An attacker who observes a valid X-Urwid-ID session token (transmitted in plaintext HTTP response headers) can send repeated POST requests containing non-ASCII bytes to the urwid CGI endpoint. Each malformed request causes the CGI handler to crash with HTTP 500. This results in a Denial of Service (DoS) for legitimate users using the urwid web interface.

Affected Versions

urwid <= 4.0.6

Patches

Fixed in urwid 4.0.7. Users should upgrade to version 4.0.7 or later.

Workarounds

No direct workaround exists short of disabling the urwid web display interface.

Severity
5.3 (Medium)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
References
To clipboard 

{
  "affected": [
    {
      "ecosystem_specific": {
        "fix": null,
        "range_state": "affected",
        "resource": "urwid",
        "resource_purl": "pkg:pypi/urwid@4.2.5",
        "upstream_fixed_in": "4.0.7"
      },
      "package": {
        "ecosystem": "Homebrew",
        "name": "topydo",
        "purl": "pkg:brew/topydo"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.15"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "database_specific": {
    "confidence": "high",
    "source": "matched",
    "strategy": "registry",
    "upstream_evidence": [
      {
        "ecosystem": "PyPI",
        "key": "pkg:pypi/urwid@4.2.5",
        "name": "urwid",
        "resource": "urwid",
        "strategy": "registry",
        "subject_version": "4.2.5"
      }
    ]
  },
  "details": "### Summary\nThe `handle_short_request()` function in `urwid/display/web.py` raises an unhandled `UnicodeEncodeError` when processing a POST request body containing non-ASCII bytes. The function reads POST input and encodes it to ASCII before writing to a named pipe. Any byte value above `0x7F` causes the CGI process to exit with an unhandled exception, returning an HTTP 500 error to the client. Additionally, a file descriptor opened earlier in the same function is not closed before the exception propagates, causing a file descriptor leak for the lifetime of the CGI process.\n\nA second instance of missing exception handling exists in the polling update path, where non-UTF-8 socket output causes an unhandled `UnicodeDecodeError`.\n\n### Impact\nAn attacker who observes a valid `X-Urwid-ID` session token (transmitted in plaintext HTTP response headers) can send repeated POST requests containing non-ASCII bytes to the `urwid` CGI endpoint. Each malformed request causes the CGI handler to crash with HTTP 500. This results in a Denial of Service (DoS) for legitimate users using the `urwid` web interface.\n\n### Affected Versions\n`urwid \u003c= 4.0.6`\n\n### Patches\nFixed in `urwid 4.0.7`. Users should upgrade to version `4.0.7` or later.\n\n### Workarounds\nNo direct workaround exists short of disabling the `urwid` web display interface.",
  "id": "BREW-topydo-CVE-2026-103022",
  "modified": "2026-11-10T11:04:51Z",
  "published": "2026-11-10T11:04:51Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/urwid/urwid/security/advisories/GHSA-cp25-j9x5-p5xm"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-103022"
    },
    {
      "type": "WEB",
      "url": "https://github.com/urwid/urwid/pull/1201"
    },
    {
      "type": "WEB",
      "url": "https://github.com/urwid/urwid/commit/b79d9a96843a6f5950bb2bfab5d059bdc61c538b"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/urwid/urwid"
    },
    {
      "type": "WEB",
      "url": "https://github.com/urwid/urwid/releases/tag/4.0.7"
    }
  ],
  "schema_version": "1.7.3",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Urwid: handle_short_request() crashes on non-ASCII POST body (UnicodeEncodeError DoS)",
  "upstream": [
    "GHSA-cp25-j9x5-p5xm",
    "CVE-2026-103022"
  ]
}



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