{"affected":[{"defaultStatus":"unaffected","product":"Linux","source":"CNA: Linux","vendor":"Linux","versions":[{"lessThan":"ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e","status":"affected","version":"3f364222d032eea6b245780e845ad213dab28cdd","versionType":"git"},{"lessThan":"ddc34a1b85505c919026ddc82fafdada9a160b15","status":"affected","version":"3f364222d032eea6b245780e845ad213dab28cdd","versionType":"git"},{"lessThan":"0db169a91381a473b7974021d1c02f8da72c5775","status":"affected","version":"3f364222d032eea6b245780e845ad213dab28cdd","versionType":"git"},{"lessThan":"d7b87adeb0eb539b9b824b101bb14fb01e41240b","status":"affected","version":"3f364222d032eea6b245780e845ad213dab28cdd","versionType":"git"},{"lessThan":"57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52","status":"affected","version":"3f364222d032eea6b245780e845ad213dab28cdd","versionType":"git"},{"lessThan":"6557f1565d779851c4db9c488c49c05a47a6e72f","status":"affected","version":"3f364222d032eea6b245780e845ad213dab28cdd","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","source":"CNA: Linux","vendor":"Linux","versions":[{"status":"affected","version":"5.18"},{"lessThan":"5.18","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"6.1.*","status":"unaffected","version":"6.1.165","versionType":"semver"},{"lessThanOrEqual":"6.6.*","status":"unaffected","version":"6.6.128","versionType":"semver"},{"lessThanOrEqual":"6.12.*","status":"unaffected","version":"6.12.75","versionType":"semver"},{"lessThanOrEqual":"6.18.*","status":"unaffected","version":"6.18.14","versionType":"semver"},{"lessThanOrEqual":"6.19.*","status":"unaffected","version":"6.19.4","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.0","versionType":"original_commit_for_fix"}]}],"cveId":"CVE-2026-45886","cwes":[],"description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix bpf_xdp_store_bytes proto for read-only arg\n\nWhile making some maps in Cilium read-only from the BPF side, we noticed\nthat the bpf_xdp_store_bytes proto is incorrect. In particular, the\nverifier was throwing the following error:\n\n  ; ret = ctx_store_bytes(ctx, l3_off + offsetof(struct iphdr, saddr),\n                          &nat->address, 4, 0);\n  635: (79) r1 = *(u64 *)(r10 -144)     ; R1=ctx() R10=fp0 fp-144=ctx()\n  636: (b4) w2 = 26                     ; R2=26\n  637: (b4) w4 = 4                      ; R4=4\n  638: (b4) w5 = 0                      ; R5=0\n  639: (85) call bpf_xdp_store_bytes#190\n  write into map forbidden, value_size=6 off=0 size=4\n\nnat comes from a BPF_F_RDONLY_PROG map, so R3 is a PTR_TO_MAP_VALUE.\nThe verifier checks the helper's memory access to R3 in\ncheck_mem_size_reg, as it reaches ARG_CONST_SIZE argument. The third\nargument has expected type ARG_PTR_TO_UNINIT_MEM, which includes the\nMEM_WRITE flag. The verifier thus checks for a BPF_WRITE access on R3.\nGiven R3 points to a read-only map, the check fails.\n\nConversely, ARG_PTR_TO_UNINIT_MEM can also lead to the helper reading\nfrom uninitialized memory.\n\nThis patch simply fixes the expected argument type to match that of\nbpf_skb_store_bytes.","epss":{"date":"2026-11-06","percentile":0.0527,"score":0.0016},"exploits":[],"kev":null,"metrics":[],"modifiedAt":1793980390803,"publishedAt":1779884218000,"references":[{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/ddc34a1b85505c919026ddc82fafdada9a160b15"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/0db169a91381a473b7974021d1c02f8da72c5775"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/d7b87adeb0eb539b9b824b101bb14fb01e41240b"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52"},{"source":"CNA: Linux","tags":[],"url":"https://git.kernel.org/stable/c/6557f1565d779851c4db9c488c49c05a47a6e72f"}],"remediation":[],"revision":"3fa4c133f64409a91016b274d6990b6dca00c33d7afd05929874fd9c22ed721d","sources":[{"modifiedAt":1793980390803,"name":"CNA: Linux","retrievedAt":1793981760956,"url":"https://www.cve.org/CVERecord?id=CVE-2026-45886"},{"modifiedAt":null,"name":"FIRST EPSS","retrievedAt":1793981787608,"url":"https://api.first.org/data/v1/epss?cve=CVE-2026-45886"}],"ssvc":{"assessedAt":1793979812501,"automatable":"no","exploitation":"none","source":"ADP: CISA-ADP","technicalImpact":"partial"},"status":"published","title":"bpf: Fix bpf_xdp_store_bytes proto for read-only arg","updatedAt":1793981787608}