LiveActive security incident?Get immediate response
CVE Record

CVE-2024-26589: bpf: Reject variable offset alu on PTR_TO_FLOW_KEYS

In the Linux kernel, the following vulnerability has been resolved: bpf: Reject variable offset alu on PTR_TO_FLOW_KEYS For PTR_TO_FLOW_KEYS, check_flow_keys_access() only uses fixed off for validation. However, variable offset ptr alu is not prohibited for this ptr kind. So the variable offset is not checked. The following prog is accepted: func#0 @0 0: R1=ctx() R10=fp0 0: (bf) r6 = r1 ; R1=ctx() R6_w=ctx() 1: (79) r7 = *(u64 *)(r6 +144) ; R6_w=ctx() R7_w=flow_keys() 2: (b7) r8 = 1024 ; R8_w=1024 3: (37) r8 /= 1 ; R8_w=scalar() 4: (57) r8 &= 1024 ; R8_w=scalar(smin=smin32=0, smax=umax=smax32=umax32=1024,var_off=(0x0; 0x400)) 5: (0f) r7 += r8 mark_precise: frame0: last_idx 5 first_idx 0 subseq_idx -1 mark_precise: frame0: regs=r8 stack= before 4: (57) r8 &= 1024 mark_precise: frame0: regs=r8 stack= before 3: (37) r8 /= 1 mark_precise: frame0: regs=r8 stack= before 2: (b7) r8 = 1024 6: R7_w=flow_keys(smin=smin32=0,smax=umax=smax32=umax32=1024,var_off =(0x0; 0x400)) R8_w=scalar(smin=smin32=0,smax=umax=smax32=umax32=1024, var_off=(0x0; 0x400)) 6: (79) r0 = *(u64 *)(r7 +0) ; R0_w=scalar() 7: (95) exit This prog loads flow_keys to r7, and adds the variable offset r8 to r7, and finally causes out-of-bounds access: BUG: unable to handle page fault for address: ffffc90014c80038 [...] Call Trace: <TASK> bpf_dispatcher_nop_func include/linux/bpf.h:1231 [inline] __bpf_prog_run include/linux/filter.h:651 [inline] bpf_prog_run include/linux/filter.h:658 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:675 [inline] bpf_flow_dissect+0x15f/0x350 net/core/flow_dissector.c:991 bpf_prog_test_run_flow_dissector+0x39d/0x620 net/bpf/test_run.c:1359 bpf_prog_test_run kernel/bpf/syscall.c:4107 [inline] __sys_bpf+0xf8f/0x4560 kernel/bpf/syscall.c:5475 __do_sys_bpf kernel/bpf/syscall.c:5561 [inline] __se_sys_bpf kernel/bpf/syscall.c:5559 [inline] __x64_sys_bpf+0x73/0xb0 kernel/bpf/syscall.c:5559 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0x3f/0x110 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x63/0x6b Fix this by rejecting ptr alu with variable offset on flow_keys. Applying the patch rejects the program with "R7 pointer arithmetic on flow_keys prohibited".

UnknownCVSS not scoredNot KEV-listedUpdated
Discuss exposureBack to CVEs
Glexia's TakeAutomated analysismoderate

Security readout for executives and security teams

Plain-English summary

CVE-2024-26589 is a Linux kernel eBPF verifier flaw. A specially crafted BPF flow dissector program could bypass offset validation and trigger out-of-bounds kernel memory access, demonstrated as a kernel page fault. Public sources do not show active exploitation.

Executive priority

Treat this as a kernel maintenance item with moderate urgency. Patch exposed Linux fleets during normal security update windows, faster where BPF access is broadly available or hosts run multi-tenant workloads.

Technical view

PTR_TO_FLOW_KEYS validation checked only fixed offsets, while variable-offset pointer arithmetic was still accepted. That let a BPF program adjust a flow_keys pointer with an unchecked variable offset and read out of bounds. The kernel fix rejects variable-offset pointer arithmetic on flow_keys.

Likely exposure

Exposure is most relevant on Linux systems running affected kernel versions or downstream builds without the stable backport. Practical exposure depends on who can load or test BPF programs on the host, which the sources do not specify.

Exploitation context

The source describes a verifier-accepted proof case causing a page fault through bpf_prog_test_run_flow_dissector. CISA KEV status is false in the supplied bundle, and no cited source states in-the-wild exploitation.

Researcher notes

Evidence supports an eBPF verifier logic bug and kernel crash path, but not a confirmed privilege escalation or active exploitation. Validate using patch presence and vendor advisories rather than attempting to reproduce the crashing program in production.

Mitigation direction

  • Update to a vendor kernel containing the listed stable fixes or equivalent backports.
  • Prioritize systems where untrusted users or services can load BPF programs.
  • Check Linux distribution advisories for supported package names and fixed build numbers.
  • Avoid relying on unofficial workarounds unless your kernel vendor documents them.

Validation and detection

  • Inventory Linux kernel versions across servers, containers hosts, and appliances.
  • Confirm vendor kernel packages include a backport for CVE-2024-26589.
  • Check whether fleet policy permits untrusted BPF program loading.
  • Track KEV and vendor advisories for exploitation or severity changes.
Prepared
Confidence
high
Sources
7

Public sources used

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.

ATT&CK lookup starting points

Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.

cve · low confidence lookup

CVE-2024-26589 mapping review

Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.

Open ATT&CK lookup
Vulnerability profileCVE Program record
Severity
Unknown
CVSS
Not scored
Known Exploited
No
Published
Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

0CVSS vectors
3Timeline events
2ADP providers
6Source links

SSVC decision data

CISA-ADPCISA Coordinator
Timestamp
Version
2.0.3
Exploitation: noneAutomatable: noTechnical Impact: partial

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

ADP provider summaries

CISA-ADPCISA ADP Vulnrichment
other:ssvc
CVECVE Program Container

Source materials

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxd58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9, d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9, d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9, d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9, d58e468b1112dcd1d5193c0a89ff9f98b5a3e8b9unaffected
LinuxLinux4.20, 0, 5.15.148, 6.1.75, 6.6.14, 6.7.2, 6.8affected
Weakness

CWE details

No CWE listed

CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.