CVE-2022-50219

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix KASAN use-after-free Read in compute_effective_progs Syzbot found a Use After Free bug in compute_effective_progs(). The reproducer creates a number of BPF links, and causes a fault injected alloc to fail, while calling bpf_link_detach on them. Link detach triggers the link to be freed by bpf_link_free(), which calls __cgroup_bpf_detach() and update_effective_progs(). If the memory allocation in this function fails, the function restores the pointer to the bpf_cgroup_link on the cgroup list, but the memory gets freed just after it returns. After this, every subsequent call to update_effective_progs() causes this already deallocated pointer to be dereferenced in prog_list_length(), and triggers KASAN UAF error. To fix this issue don't preserve the pointer to the prog or link in the list, but remove it and replace it with a dummy prog without shrinking the table. The subsequent call to __cgroup_bpf_detach() or __cgroup_bpf_detach() will correct it.

CVSS v3 7.8 HIGH

7.8^/10

CVSS v3 : HIGH

Vector :

Exploitability : 1.8 / Impact : 5.9

Attack Vector LOCAL

Attack Complexity LOW

Privileges Required LOW

User Interaction NONE

Confidentiality Impact HIGH

Integrity Impact HIGH

Availability Impact HIGH

Scope UNCHANGED

References

Link	Resource
https://git.kernel.org/stable/c/1f8ca9c40e6222ce431e9ba5dae3cccce8ef9443	Patch
https://git.kernel.org/stable/c/3527e3cbb84d8868c4d4e91ba55915f96d39ec3d	Patch
https://git.kernel.org/stable/c/4c46091ee985ae84c60c5e95055d779fcd291d87	Patch
https://git.kernel.org/stable/c/6336388715afa419cc97d0255bda3bba1b96b7ca	Patch
https://git.kernel.org/stable/c/be001f9da71eaa3b61e186fb88bde3279728bdca	Patch

Configurations

Configuration 1 (hide)

OR	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::
	cpe:2.3:o:linux:linux_kernel::::::::

History

No history.

Information

Published : 2025-06-18 11:15

Updated : 2025-11-19 12:59

NVD link : CVE-2022-50219

Mitre link : CVE-2022-50219

CVE.ORG link : CVE-2022-50219

JSON object : View

Products Affected

linux

linux_kernel

CWE

CWE-416

Use After Free

{"id": "CVE-2022-50219", "cveTags": [], "metrics": {"cvssMetricV31": [{"type": "Primary", "source": "nvd@nist.gov", "cvssData": {"scope": "UNCHANGED", "version": "3.1", "baseScore": 7.8, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "integrityImpact": "HIGH", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH"}, "impactScore": 5.9, "exploitabilityScore": 1.8}]}, "published": "2025-06-18T11:15:52.863", "references": [{"url": "https://git.kernel.org/stable/c/1f8ca9c40e6222ce431e9ba5dae3cccce8ef9443", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/3527e3cbb84d8868c4d4e91ba55915f96d39ec3d", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/4c46091ee985ae84c60c5e95055d779fcd291d87", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/6336388715afa419cc97d0255bda3bba1b96b7ca", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}, {"url": "https://git.kernel.org/stable/c/be001f9da71eaa3b61e186fb88bde3279728bdca", "tags": ["Patch"], "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}], "vulnStatus": "Analyzed", "weaknesses": [{"type": "Primary", "source": "nvd@nist.gov", "description": [{"lang": "en", "value": "CWE-416"}]}], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix KASAN use-after-free Read in compute_effective_progs\n\nSyzbot found a Use After Free bug in compute_effective_progs().\nThe reproducer creates a number of BPF links, and causes a fault\ninjected alloc to fail, while calling bpf_link_detach on them.\nLink detach triggers the link to be freed by bpf_link_free(),\nwhich calls __cgroup_bpf_detach() and update_effective_progs().\nIf the memory allocation in this function fails, the function restores\nthe pointer to the bpf_cgroup_link on the cgroup list, but the memory\ngets freed just after it returns. After this, every subsequent call to\nupdate_effective_progs() causes this already deallocated pointer to be\ndereferenced in prog_list_length(), and triggers KASAN UAF error.\n\nTo fix this issue don't preserve the pointer to the prog or link in the\nlist, but remove it and replace it with a dummy prog without shrinking\nthe table. The subsequent call to __cgroup_bpf_detach() or\n__cgroup_bpf_detach() will correct it."}, {"lang": "es", "value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: bpf: Correcci\u00f3n de la lectura de Use-After-Free de KASAN en compute_effective_progs Syzbot encontr\u00f3 un error de Use-After-Free en compute_effective_progs(). El reproductor crea varios enlaces BPF y provoca que falle una asignaci\u00f3n inyectada por error, al llamar a bpf_link_detach en ellos. La separaci\u00f3n del enlace activa la liberaci\u00f3n del enlace por bpf_link_free(), que llama a __cgroup_bpf_detach() y update_effective_progs(). Si la asignaci\u00f3n de memoria en esta funci\u00f3n falla, la funci\u00f3n restaura el puntero a bpf_cgroup_link en la lista cgroup, pero la memoria se libera justo despu\u00e9s de que regrese. Despu\u00e9s de esto, cada llamada posterior a update_effective_progs() hace que este puntero ya desasignado se desreferencia en prog_list_length() y activa el error UAF de KASAN. Para solucionar este problema, no conserve el puntero al programa ni al enlace en la lista, sino elim\u00ednelo y reempl\u00e1celo con un programa ficticio sin reducir la tabla. La llamada posterior a __cgroup_bpf_detach() o __cgroup_bpf_detach() lo corregir\u00e1. "}], "lastModified": "2025-11-19T12:59:32.937", "configurations": [{"nodes": [{"negate": false, "cpeMatch": [{"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "E036C6FE-698D-47B5-997F-8EF2A4EB00D6", "versionEndExcluding": "5.10.138", "versionStartIncluding": "5.7"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "51861563-7F40-460F-82CD-2D3FBDAD6618", "versionEndExcluding": "5.15.61", "versionStartIncluding": "5.11"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "5B42E453-8837-49D0-A5EF-03F818A6DC11", "versionEndExcluding": "5.18.18", "versionStartIncluding": "5.16"}, {"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "vulnerable": true, "matchCriteriaId": "A1A2A5A5-4598-4D7E-BA07-4660398D6C8F", "versionEndExcluding": "5.19.2", "versionStartIncluding": "5.19"}], "operator": "OR"}]}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"}