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CVE-2026-45886· NVD / CVE Program· CNA Linux

bpf: Fix bpf_xdp_store_bytes proto for read-only arg

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix bpf_xdp_store_bytes proto for read-only arg While making some maps in Cilium read-only from the BPF side, we noticed that the bpf_xdp_store_bytes proto is incorrect. In particular, the verifier was throwing the following error: ; ret = ctx_store_bytes(ctx, l3_off + offsetof(struct iphdr, saddr), &nat->address, 4, 0); 635: (79) r1 = *(u64 *)(r10 -144) ; R1=ctx() R10=fp0 fp-144=ctx() 636: (b4) w2 = 26 ; R2=26 637: (b4) w4 = 4 ; R4=4 638: (b4) w5 = 0 ; R5=0 639: (85) call bpf_xdp_store_bytes#190 write into map forbidden, value_size=6 off=0 size=4 nat comes from a BPF_F_RDONLY_PROG map, so R3 is a PTR_TO_MAP_VALUE. The verifier checks the helper's memory access to R3 in check_mem_size_reg, as it reaches ARG_CONST_SIZE argument. The third argument has expected type ARG_PTR_TO_UNINIT_MEM, which includes the MEM_WRITE flag. The verifier thus checks for a BPF_WRITE access on R3. Given R3 points to a read-only map, the check fails. Conversely, ARG_PTR_TO_UNINIT_MEM can also lead to the helper reading from uninitialized memory. This patch simply fixes the expected argument type to match that of bpf_skb_store_bytes.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 27, 2026
Updated
Jun 25, 2026
EPSS
0.2% · 5th percentile
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JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

Noroxi analysis

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Affected systems

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernel5.18 and later · before 6.1.165
  • linux linux kernel6.2 and later · before 6.6.128
  • linux linux kernel6.7 and later · before 6.12.75
  • linux linux kernel6.13 and later · before 6.18.14
  • linux linux kernel6.19 and later · before 6.19.4

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 5.18affected
    • 3f364222d032eea6b245780e845ad213dab28cdd and later · before ffb5d1c5e3933b947fc7303ad68bf0c536d0c85eaffected · git
    • 3f364222d032eea6b245780e845ad213dab28cdd and later · before ddc34a1b85505c919026ddc82fafdada9a160b15affected · git
    • 3f364222d032eea6b245780e845ad213dab28cdd and later · before 0db169a91381a473b7974021d1c02f8da72c5775affected · git
    • 3f364222d032eea6b245780e845ad213dab28cdd and later · before d7b87adeb0eb539b9b824b101bb14fb01e41240baffected · git
    • 3f364222d032eea6b245780e845ad213dab28cdd and later · before 57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52affected · git
    • 3f364222d032eea6b245780e845ad213dab28cdd and later · before 6557f1565d779851c4db9c488c49c05a47a6e72faffected · git
    • before 5.18not affected · semver
    • 6.1.165 and later · up to and including 6.1.*not affected · semver
    • 6.6.128 and later · up to and including 6.6.*not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.170-16.1.170-1
Debian:13linuxbefore 6.12.85-16.12.85-1
Debian:14linuxbefore 6.18.14-16.18.14-1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOSkernel-64kbbefore 5.14.21-150500.55.172.25.14.21-150500.55.172.2
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOSkernel-docsbefore 5.14.21-150500.55.172.15.14.21-150500.55.172.1
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOSkernel-obs-buildbefore 5.14.21-150500.55.172.25.14.21-150500.55.172.2
SUSE:Linux Enterprise High Performance Computing 15 SP5-ESPOSkernel-symsbefore 5.14.21-150500.55.172.15.14.21-150500.55.172.1
SUSE:Linux Enterprise Live Patching 15 SP5kernel-livepatch-SLE15-SP5_Update_42before 1-150500.11.3.21-150500.11.3.2
SUSE:Linux Enterprise Live Patching 15 SP6kernel-defaultbefore 6.4.0-150600.23.118.16.4.0-150600.23.118.1
SUSE:Linux Enterprise Live Patching 15 SP6kernel-livepatch-SLE15-SP6_Update_28before 1-150600.13.3.11-150600.13.3.1
SUSE:Linux Enterprise Micro 5.5kernel-defaultbefore 5.14.21-150500.55.172.25.14.21-150500.55.172.2
SUSE:Linux Enterprise Micro 5.5kernel-default-basebefore 5.14.21-150500.55.172.2.150500.6.81.25.14.21-150500.55.172.2.150500.6.81.2
SUSE:Linux Enterprise Micro 5.5kernel-rtbefore 5.14.21-150500.13.146.15.14.21-150500.13.146.1
SUSE:Linux Enterprise Micro 5.5kernel-sourcebefore 5.14.21-150500.55.172.25.14.21-150500.55.172.2
SUSE:Linux Enterprise Micro 5.5kernel-source-rtbefore 5.14.21-150500.13.146.15.14.21-150500.13.146.1
SUSE:Linux Enterprise Server 15 SP5-LTSSkernel-zfcpdumpbefore 5.14.21-150500.55.172.25.14.21-150500.55.172.2
SUSE:Linux Enterprise Server 15 SP6-LTSSkernel-64kbbefore 6.4.0-150600.23.118.16.4.0-150600.23.118.1
SUSE:Linux Enterprise Server 15 SP6-LTSSkernel-default-basebefore 6.4.0-150600.23.118.1.150600.12.56.16.4.0-150600.23.118.1.150600.12.56.1
SUSE:Linux Enterprise Server 15 SP6-LTSSkernel-docsbefore 6.4.0-150600.23.118.16.4.0-150600.23.118.1
SUSE:Linux Enterprise Server 15 SP6-LTSSkernel-obs-buildbefore 6.4.0-150600.23.118.16.4.0-150600.23.118.1
SUSE:Linux Enterprise Server 15 SP6-LTSSkernel-sourcebefore 6.4.0-150600.23.118.16.4.0-150600.23.118.1
SUSE:Linux Enterprise Server 15 SP6-LTSSkernel-symsbefore 6.4.0-150600.23.118.16.4.0-150600.23.118.1
SUSE:Linux Enterprise Server 15 SP6-LTSSkernel-zfcpdumpbefore 6.4.0-150600.23.118.16.4.0-150600.23.118.1

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Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux0db169a91381a473b7974021d1c02f8da72c5775Vendor (CNA)
Linux Linux57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52Vendor (CNA)
Linux Linux6557f1565d779851c4db9c488c49c05a47a6e72fVendor (CNA)
Linux Linuxd7b87adeb0eb539b9b824b101bb14fb01e41240bVendor (CNA)
Linux Linuxddc34a1b85505c919026ddc82fafdada9a160b15Vendor (CNA)
Linux Linuxffb5d1c5e3933b947fc7303ad68bf0c536d0c85eVendor (CNA)
debian:linux6.1.170-1 · Debian:12Package registry (OSV)
suse:kernel-64kb6.4.0-150600.23.118.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-default6.4.0-150600.23.118.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-default-base6.4.0-150600.23.118.1.150600.12.56.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-docs6.4.0-150600.23.118.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-livepatch-SLE15-SP5_Update_421-150500.11.3.2 · SUSE:Linux Enterprise Live Patching 15 SP5Package registry (OSV)
suse:kernel-livepatch-SLE15-SP6_Update_281-150600.13.3.1 · SUSE:Linux Enterprise Live Patching 15 SP6Package registry (OSV)
suse:kernel-obs-build6.4.0-150600.23.118.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-rt5.14.21-150500.13.146.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-source6.4.0-150600.23.118.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-source-rt5.14.21-150500.13.146.1 · SUSE:Linux Enterprise Micro 5.5Package registry (OSV)
suse:kernel-syms6.4.0-150600.23.118.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)
suse:kernel-zfcpdump6.4.0-150600.23.118.1 · SUSE:Linux Enterprise Server 15 SP6-LTSSPackage registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-5298928 days apartnvmet-tcp: propagate nvmet_tcp_build_pdu_iovec() errors to its callers
    39Monitor
  • CVE-2026-5322529 days apartsctp: fix uninit-value in __sctp_rcv_asconf_lookup()
    36Monitor
  • CVE-2026-5317029 days apartaccel/ethosu: reject DMA commands with uninitialized length
    35Monitor
  • CVE-2026-4313921 days apartxfrm6: fix uninitialized saddr in xfrm6_get_saddr()
    34Monitor
  • CVE-2026-4329119 days apartnet: nfc: nci: Fix parameter validation for packet data
    33Monitor
  • CVE-2026-4345619 days apartbonding: fix type confusion in bond_setup_by_slave()
    31Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

All records