CVE-2022-49264 (GCVE-0-2022-49264)

Vulnerability from cvelistv5 – Published: 2025-02-26 01:56 – Updated: 2026-08-05 08:54
VLAI
Title
exec: Force single empty string when argv is empty
Summary
In the Linux kernel, the following vulnerability has been resolved: exec: Force single empty string when argv is empty Quoting[1] Ariadne Conill: "In several other operating systems, it is a hard requirement that the second argument to execve(2) be the name of a program, thus prohibiting a scenario where argc < 1. POSIX 2017 also recommends this behaviour, but it is not an explicit requirement[2]: The argument arg0 should point to a filename string that is associated with the process being started by one of the exec functions. ... Interestingly, Michael Kerrisk opened an issue about this in 2008[3], but there was no consensus to support fixing this issue then. Hopefully now that CVE-2021-4034 shows practical exploitative use[4] of this bug in a shellcode, we can reconsider. This issue is being tracked in the KSPP issue tracker[5]." While the initial code searches[6][7] turned up what appeared to be mostly corner case tests, trying to that just reject argv == NULL (or an immediately terminated pointer list) quickly started tripping[8] existing userspace programs. The next best approach is forcing a single empty string into argv and adjusting argc to match. The number of programs depending on argc == 0 seems a smaller set than those calling execve with a NULL argv. Account for the additional stack space in bprm_stack_limits(). Inject an empty string when argc == 0 (and set argc = 1). Warn about the case so userspace has some notice about the change: process './argc0' launched './argc0' with NULL argv: empty string added Additionally WARN() and reject NULL argv usage for kernel threads. [1] https://lore.kernel.org/lkml/20220127000724.15106-1-ariadne@dereferenced.org/ [2] https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html [3] https://bugzilla.kernel.org/show_bug.cgi?id=8408 [4] https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt [5] https://github.com/KSPP/linux/issues/176 [6] https://codesearch.debian.net/search?q=execve%5C+*%5C%28%5B%5E%2C%5D%2B%2C+*NULL&literal=0 [7] https://codesearch.debian.net/search?q=execlp%3F%5Cs*%5C%28%5B%5E%2C%5D%2B%2C%5Cs*NULL&literal=0 [8] https://lore.kernel.org/lkml/20220131144352.GE16385@xsang-OptiPlex-9020/
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version
Linux Linux Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 41f6ea5b9aaa28b740d47ffe995a5013211fdbb0 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 98e0c7c702894987732776736c99b85ade6fba45 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < b50fb8dbc8b81aaa126387de428f4c42a7c72a73 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 1fe82bfd9e4ce93399d815ca458b58505191c3e8 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 27a6f495b63a1804cc71be45911065db7757a98c (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < 1290eb4412aa0f0e9f3434b406dc8e255da85f9e (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < a8054d3fa5deb84b215d6be1b910a978f3cb840d (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < cfbfff8ce5e3d674947581f1eb9af0a1b1807950 (git)
Affected: 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 , < dcd46d897adb70d63e025f175a00a89797d31a43 (git)
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Linux Linux Affected: 2.6.12
Unaffected: 0 , < 2.6.12 (semver)
Unaffected: 4.9.317 , ≤ 4.9.* (semver)
Unaffected: 4.14.282 , ≤ 4.14.* (semver)
Unaffected: 4.19.246 , ≤ 4.19.* (semver)
Unaffected: 5.4.197 , ≤ 5.4.* (semver)
Unaffected: 5.10.110 , ≤ 5.10.* (semver)
Unaffected: 5.15.33 , ≤ 5.15.* (semver)
Unaffected: 5.16.19 , ≤ 5.16.* (semver)
Unaffected: 5.17.2 , ≤ 5.17.* (semver)
Unaffected: 5.18 , ≤ * (original_commit_for_fix)
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nexec: Force single empty string when argv is empty\n\nQuoting[1] Ariadne Conill:\n\n\"In several other operating systems, it is a hard requirement that the\nsecond argument to execve(2) be the name of a program, thus prohibiting\na scenario where argc \u003c 1. POSIX 2017 also recommends this behaviour,\nbut it is not an explicit requirement[2]:\n\n    The argument arg0 should point to a filename string that is\n    associated with the process being started by one of the exec\n    functions.\n...\nInterestingly, Michael Kerrisk opened an issue about this in 2008[3],\nbut there was no consensus to support fixing this issue then.\nHopefully now that CVE-2021-4034 shows practical exploitative use[4]\nof this bug in a shellcode, we can reconsider.\n\nThis issue is being tracked in the KSPP issue tracker[5].\"\n\nWhile the initial code searches[6][7] turned up what appeared to be\nmostly corner case tests, trying to that just reject argv == NULL\n(or an immediately terminated pointer list) quickly started tripping[8]\nexisting userspace programs.\n\nThe next best approach is forcing a single empty string into argv and\nadjusting argc to match. The number of programs depending on argc == 0\nseems a smaller set than those calling execve with a NULL argv.\n\nAccount for the additional stack space in bprm_stack_limits(). Inject an\nempty string when argc == 0 (and set argc = 1). Warn about the case so\nuserspace has some notice about the change:\n\n    process \u0027./argc0\u0027 launched \u0027./argc0\u0027 with NULL argv: empty string added\n\nAdditionally WARN() and reject NULL argv usage for kernel threads.\n\n[1] https://lore.kernel.org/lkml/20220127000724.15106-1-ariadne@dereferenced.org/\n[2] https://pubs.opengroup.org/onlinepubs/9699919799/functions/exec.html\n[3] https://bugzilla.kernel.org/show_bug.cgi?id=8408\n[4] https://www.qualys.com/2022/01/25/cve-2021-4034/pwnkit.txt\n[5] https://github.com/KSPP/linux/issues/176\n[6] https://codesearch.debian.net/search?q=execve%5C+*%5C%28%5B%5E%2C%5D%2B%2C+*NULL\u0026literal=0\n[7] https://codesearch.debian.net/search?q=execlp%3F%5Cs*%5C%28%5B%5E%2C%5D%2B%2C%5Cs*NULL\u0026literal=0\n[8] https://lore.kernel.org/lkml/20220131144352.GE16385@xsang-OptiPlex-9020/"
        }
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            "baseSeverity": "HIGH",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
            "version": "3.1"
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              "value": "AV:L - The vulnerability is triggered via the local execve/execveat syscalls in do_execveat_common(); an attacker must already have local code execution to pass a NULL or empty argv. It is not reachable by receiving network packets or remote protocol handling.\nAC:L - The attacker fully controls the argv passed to execve and can reliably invoke setuid helpers with argc==0; PwnKit demonstrated instant, architecture-independent exploitation with no race or layout precondition outside attacker control.\nPR:L - Any unprivileged local user can call execve on a setuid binary such as pkexec; the syscall path imposes no capability checks, and setuid credential elevation occurs normally via bprm_fill_uid.\nUI:N - The attacker alone performs the empty-argv execve of the setuid target; no separate victim action such as mounting a filesystem or opening a file is required.\nS:U - Impact is local privilege escalation to root within the same host OS security authority, not a VM escape, IOMMU bypass, or other cross-boundary compromise.\nC:H - Empty argv makes argv[1] alias envp[0] so confused setuid programs can reintroduce sanitized variables and run attacker code as root, yielding full confidentiality compromise as demonstrated by CVE-2021-4034.\nI:H - The same argv/envp confusion enables out-of-bounds writes into the environment of a privileged process and arbitrary root code execution, fully compromising integrity at the privilege boundary.\nA:H - Successful exploitation yields unrestricted root on the host, which includes the ability to halt or crash the system; standard local privilege-escalation scoring therefore assigns Availability High."
            }
          ]
        }
      ],
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        "dateUpdated": "2026-08-05T08:54:30.630Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/41f6ea5b9aaa28b740d47ffe995a5013211fdbb0"
        },
        {
          "url": "https://git.kernel.org/stable/c/98e0c7c702894987732776736c99b85ade6fba45"
        },
        {
          "url": "https://git.kernel.org/stable/c/b50fb8dbc8b81aaa126387de428f4c42a7c72a73"
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        {
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        },
        {
          "url": "https://git.kernel.org/stable/c/dcd46d897adb70d63e025f175a00a89797d31a43"
        }
      ],
      "title": "exec: Force single empty string when argv is empty",
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2022-49264",
    "datePublished": "2025-02-26T01:56:14.664Z",
    "dateReserved": "2025-02-26T01:49:39.296Z",
    "dateUpdated": "2026-08-05T08:54:30.630Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2022-49264",
      "date": "2026-10-03",
      "epss": "0.00305",
      "percentile": "0.21147"
    }
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.