CVE-2026-90210 (GCVE-0-2026-90210)

Vulnerability from cvelistv5 – Published: 2026-09-17 16:07 – Updated: 2026-10-19 08:59
VLAI
Title
bpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure When bpf_trampoline_update() fails before modify_fentry_multi()/ unregister_fentry_multi() is called, cur_image is unchanged (cur_image == old_image) and ftrace still calls into it. Freeing old_image in that case causes a UAF. Only free old_image when it differs from cur_image.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
Linux CNA under the mitre root
CNA scorecard D 53/100 over 6639 records in the last 180 days details
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: aef4dfa790b22d8052cfb78044eadbe03c876c39 , < 65c3939656fd7848e9274faa07c26748b5bf049c (git)
Affected: aef4dfa790b22d8052cfb78044eadbe03c876c39 , < 0253073fb7d79a2dd2eae9581ea16db2aef395a6 (git)
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Linux Linux Affected: 7.2
Unaffected: 0 , < 7.2 (semver)
Unaffected: 7.2.6 , ≤ 7.2.* (semver)
Unaffected: 7.3 , ≤ * (original_commit_for_fix)
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{
  "containers": {
    "cna": {
      "affected": [
        {
          "defaultStatus": "unaffected",
          "product": "Linux",
          "programFiles": [
            "kernel/bpf/trampoline.c"
          ],
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
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              "status": "unaffected",
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              "versionType": "original_commit_for_fix"
            }
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      "cpeApplicability": [
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                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.2.6",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                },
                {
                  "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                  "versionEndExcluding": "7.3",
                  "versionStartIncluding": "7.2",
                  "vulnerable": true
                }
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              "negate": false,
              "operator": "OR"
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      "descriptions": [
        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure\n\nWhen bpf_trampoline_update() fails before modify_fentry_multi()/\nunregister_fentry_multi() is called, cur_image is unchanged\n(cur_image == old_image) and ftrace still calls into it.  Freeing\nold_image in that case causes a UAF.\n\nOnly free old_image when it differs from cur_image."
        }
      ],
      "metrics": [
        {
          "cvssV3_1": {
            "baseScore": 7.8,
            "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"
          },
          "scenarios": [
            {
              "lang": "en",
              "value": "AV:L - The UAF is reached only via the local bpf() syscall: BPF_PROG_LOAD of BPF_PROG_TYPE_TRACING with BPF_TRACE_FENTRY_MULTI/FEXIT_MULTI/FSESSION_MULTI, BPF_LINK_CREATE into bpf_tracing_multi_attach(), then close() of that link fd which runs bpf_tracing_multi_link_release() -\u003e bpf_trampoline_multi_detach() -\u003e bpf_trampoline_multi_attach_free().\nAC:L - The attacker attaches a second fentry program on the same ftrace-managed function so detach rebuilds the trampoline, then closes the multi-link fd. bpf_trampoline_multi_detach() WARN_ON_ONCE-ignores bpf_trampoline_update() failure before modify_fentry_multi() and still calls bpf_trampoline_multi_attach_free(); ENOMEM from bpf_tramp_image_alloc() or arch_prepare_bpf_trampoline() is inducible by exhausting bpf_prog_pack from that process.\nPR:L - bpf_prog_load() requires bpf_token_capable(CAP_BPF) and bpf_token_capable(CAP_PERFMON) for BPF_PROG_TYPE_TRACING. bpf_token_capable() calls ns_capable() on a delegated BPF token\u0027s user namespace, so a container user with a token (or a non-root tracing daemon holding only those two caps) can load and attach fentry.multi without host root.\nUI:N - The attacker loads the tracing programs, creates the tracing-multi link with BPF_LINK_CREATE, and closes their own link fd to hit bpf_trampoline_multi_attach_free(); no other user must mount, open a file, or otherwise act.\nS:U - The UAF of bpf_tramp_image and its JIT text, and any resulting kernel control-flow hijack, remain inside the host kernel; this is a standard kernel privilege-escalation defect, not a VM escape or IOMMU/guest boundary crossing.\nC:H - On the failing detach path bpf_trampoline_multi_attach_free() calls bpf_tramp_image_put() while ftrace still direct-calls that image (old_image == cur_image). After the RCU tasks-trace GP, bpf_prog_pack_free() returns those pages; reclaiming them exposes kernel/JIT contents and yields an arbitrary-read primitive.\nI:H - ftrace keeps a direct call into the trampoline that bpf_tramp_image_put() is freeing. Reclaiming the bpf_prog_pack pages with attacker-controlled BPF JIT text makes the next call of the traced function jump to chosen kernel instructions, i.e. control-flow hijack and arbitrary write.\nA:H - After bpf_tramp_image_put() of a trampoline that ftrace still invokes, the next entry to the attached kernel function jumps into freed executable memory and oopses/panics. Closing the multi-link fd retriggers this at will."
            }
          ]
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-10-19T08:59:46.406Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/65c3939656fd7848e9274faa07c26748b5bf049c"
        },
        {
          "url": "https://git.kernel.org/stable/c/0253073fb7d79a2dd2eae9581ea16db2aef395a6"
        }
      ],
      "title": "bpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure",
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  },
  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-90210",
    "datePublished": "2026-09-17T16:07:24.772Z",
    "dateReserved": "2026-09-11T19:38:34.793Z",
    "dateUpdated": "2026-10-19T08:59:46.406Z",
    "state": "PUBLISHED"
  },
  "dataType": "CVE_RECORD",
  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
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      "date": "2026-11-09",
      "epss": "0.00165",
      "percentile": "0.05754"
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                "programFiles": [
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                    "versionType": "git"
                  },
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        "descriptions": [
          {
            "lang": "en",
            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure\n\nWhen bpf_trampoline_update() fails before modify_fentry_multi()/\nunregister_fentry_multi() is called, cur_image is unchanged\n(cur_image == old_image) and ftrace still calls into it.  Freeing\nold_image in that case causes a UAF.\n\nOnly free old_image when it differs from cur_image."
          }
        ],
        "id": "CVE-2026-90210",
        "lastModified": "2026-10-19T09:19:11.170",
        "metrics": {
          "cvssMetricV31": [
            {
              "cvssData": {
                "attackComplexity": "LOW",
                "attackVector": "LOCAL",
                "availabilityImpact": "HIGH",
                "baseScore": 7.8,
                "baseSeverity": "HIGH",
                "confidentialityImpact": "HIGH",
                "integrityImpact": "HIGH",
                "privilegesRequired": "LOW",
                "scope": "UNCHANGED",
                "userInteraction": "NONE",
                "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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              "impactScore": 5.9,
              "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
              "type": "Secondary"
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        "published": "2026-09-17T17:17:16.217",
        "references": [
          {
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            "url": "https://git.kernel.org/stable/c/0253073fb7d79a2dd2eae9581ea16db2aef395a6"
          },
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            "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
            "url": "https://git.kernel.org/stable/c/65c3939656fd7848e9274faa07c26748b5bf049c"
          }
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        "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "vulnStatus": "Received"
      }
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    "redhat_vex": {
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      "current_release_date": "2026-11-06T01:33:19+00:00",
      "cve": "CVE-2026-90210",
      "id": "CVE-2026-90210",
      "initial_release_date": "2026-09-17T00:00:00+00:00",
      "product_status:known_not_affected": "203",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: bpf: Fix UAF in bpf_trampoline_multi_attach_free on update failure",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-90210.json",
      "version": "3"
    }
  }
}



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