Vulnerability-Lookup

RUSTSEC-2026-0278 (CVE-2026-78422)

Vulnerability from osv_rustsec – Published: 2026-08-31 12:00 – Updated: 2026-09-02 09:13 – Source website

Summary

`zbus_polkit`: authorization bypass via PID reuse

Details

Subject::new_for_owner() in the zbus_polkit crate encodes the uid entry of a unix-process polkit subject as an unsigned 32-bit integer (D-Bus type u), whereas the org.freedesktop.PolicyKit1.Authority interface specifies a signed 32-bit integer (D-Bus type i). Because of this type mismatch, polkit silently discards the caller-supplied UID and instead determines the subject's owner itself by looking up the PID in /proc, a lookup that is inherently subject to a time-of-check/time-of-use race.

Consequently, an application that passes a UID obtained from a trustworthy source — for example SO_PEERCRED Unix socket peer credentials — in order to defend against PID reuse receives no protection, and the supplied UID has no effect on the authorization decision. A local unprivileged attacker who can cause an authorized process to terminate and then win the race to have their own process assigned the same PID can be authorized under the identity of the terminated process, bypassing the polkit authorization check and performing actions the attacker is not entitled to.

This issue affects zbus_polkit before 5.1.0.

Severity

7.3 (High)


                    
                      CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

References

URL

Type

	https://crates.io/crates/zbus_polkit	PACKAGE
	https://rustsec.org/advisories/RUSTSEC-2026-0278.html	ADVISORY
	https://github.com/z-galaxy/zbus_polkit/pull/101	WEB
	https://bugzilla.suse.com/show_bug.cgi?id=1277659	WEB

JSON

To clipboard

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "privilege-escalation"
        ],
        "cvss": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [
            "zbus_polkit::Subject::new_for_owner"
          ],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "zbus_polkit",
        "purl": "pkg:cargo/zbus_polkit"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.0.0-0"
            },
            {
              "fixed": "5.1.0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [
    "CVE-2026-78422"
  ],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "`Subject::new_for_owner()` in the `zbus_polkit` crate encodes the uid entry of a unix-process polkit subject as an unsigned 32-bit integer (D-Bus type u), whereas the org.freedesktop.PolicyKit1.Authority interface specifies a signed 32-bit integer (D-Bus type i). Because of this type mismatch, polkit silently discards the caller-supplied UID and instead determines the subject\u0027s owner itself by looking up the PID in /proc, a lookup that is inherently subject to a time-of-check/time-of-use race.\n\nConsequently, an application that passes a UID obtained from a trustworthy source \u2014 for example `SO_PEERCRED` Unix socket peer credentials \u2014 in order to defend against PID reuse receives no protection, and the supplied UID has no effect on the authorization decision. A local unprivileged attacker who can cause an authorized process to terminate and then win the race to have their own process assigned the same PID can be authorized under the identity of the terminated process, bypassing the polkit authorization check and performing actions the attacker is not entitled to.\n\nThis issue affects `zbus_polkit` before 5.1.0.",
  "id": "RUSTSEC-2026-0278",
  "modified": "2026-09-02T09:13:32Z",
  "published": "2026-08-31T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/zbus_polkit"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0278.html"
    },
    {
      "type": "WEB",
      "url": "https://github.com/z-galaxy/zbus_polkit/pull/101"
    },
    {
      "type": "WEB",
      "url": "https://bugzilla.suse.com/show_bug.cgi?id=1277659"
    }
  ],
  "related": [],
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "`zbus_polkit`: authorization bypass via PID reuse"
}

CVE-2026-78422 (GCVE-0-2026-78422)

Vulnerability from cvelistv5 – Published: 2026-08-31 14:14 – Updated: 2026-09-01 14:46

Title

zbus_polkit: polkit authorization bypass via PID reuse due to incorrect D-Bus type for the subject UID

Summary

Subject::new_for_owner() in the zbus_polkit crate encodes the uid entry of a unix-process polkit subject as an unsigned 32-bit integer (D-Bus type u), whereas the org.freedesktop.PolicyKit1.Authority interface specifies a signed 32-bit integer (D-Bus type i). Because of this type mismatch, polkit silently discards the caller-supplied UID and instead determines the subject's owner itself by looking up the PID in /proc, a lookup that is inherently subject to a time-of-check/time-of-use race. Consequently, an application that passes a UID obtained from a trustworthy source — for example SO_PEERCRED Unix socket peer credentials — in order to defend against PID reuse receives no protection, and the supplied UID has no effect on the authorization decision. A local unprivileged attacker who can cause an authorized process to terminate and then win the race to have their own process assigned the same PID can be authorized under the identity of the terminated process, bypassing the polkit authorization check and performing actions the attacker is not entitled to. This issue affects zbus_polkit before 5.1.0.

Severity

7.3 (High)


                        
                          CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-01 14:46 UTC

CWE

CWE-686 - Function call with incorrect argument type
CWE-367 - Time-of-check time-of-use (TOCTOU) race condition

Assigner

suse CNA under the mitre root

CNA scorecard B 78/100 over 101 records in the last 180 days details

References

2 references

URL	Tags
https://github.com/z-galaxy/zbus_polkit/pull/101	patch
https://bugzilla.suse.com/show_bug.cgi?id=1277659	issue-tracking

Impacted products

1 product

Vendor	Product	Version
z-galaxy	zbus_polkit	Affected: 0 , < 5.1.0 (semver)

Credits

Ilya Zlobintsev

Show details on NVD website

JSON

To clipboard

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              "value": "Subject::new_for_owner() in the zbus_polkit crate encodes the uid entry of a unix-process polkit subject as an unsigned 32-bit integer (D-Bus type u), whereas the org.freedesktop.PolicyKit1.Authority interface specifies a signed 32-bit integer (D-Bus type i). Because of this type mismatch, polkit silently discards the caller-supplied UID and instead determines the subject\u0027s owner itself by looking up the PID in /proc, a lookup that is inherently subject to a time-of-check/time-of-use race.\u003cbr\u003e\u003cbr\u003eConsequently, an application that passes a UID obtained from a trustworthy source \u2014 for example SO_PEERCRED Unix socket peer credentials \u2014 in order to defend against PID reuse receives no protection, and the supplied UID has no effect on the authorization decision. A local unprivileged attacker who can cause an authorized process to terminate and then win the race to have their own process assigned the same PID can be authorized under the identity of the terminated process, bypassing the polkit authorization check and performing actions the attacker is not entitled to.\u003cbr\u003e\u003cbr\u003eThis issue affects zbus_polkit before 5.1.0."
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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

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