Answer in brief
CVE-2026-45886 records a Medium severity (CVSS 5.5) vulnerability in bpf: Fix bpf_xdp_store_bytes proto for read-only arg. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=3f364222d032eea6b245780e845ad213dab28cdd <ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e || >=3f364222d032eea6b245780e845ad213dab28cdd <ddc34a1b85505c919026ddc82fafdada9a160b15 || >=3f364222d032eea6b245780e845ad213dab28cdd <0db169a91381a473b7974021d1c02f8da72c5775 || >=3f364222d032eea6b245780e845ad213dab28cdd <d7b87adeb0eb539b9b824b101bb14fb01e41240b || >=3f364222d032eea6b245780e845ad213dab28cdd <57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52 || >=3f364222d032eea6b245780e845ad213dab28cdd <6557f1565d779851c4db9c488c49c05a47a6e72f | ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e, ddc34a1b85505c919026ddc82fafdada9a160b15, 0db169a91381a473b7974021d1c02f8da72c5775, d7b87adeb0eb539b9b824b101bb14fb01e41240b, 57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52, 6557f1565d779851c4db9c488c49c05a47a6e72f |
| Linux/Linuxgeneric | 5.18 | Not reported |
Published upstream
May 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 25, 2026
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.
Quoted source text, attributed separately from HOL analysis.
Answer in brief
CVE-2026-45886 records a Medium severity (CVSS 5.5) vulnerability in bpf: Fix bpf_xdp_store_bytes proto for read-only arg. The current sources do not mark it as known exploited. The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 5.5. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps Linux/Linux (generic), Linux/Linux (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| Linux/Linuxgeneric | >=3f364222d032eea6b245780e845ad213dab28cdd <ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e || >=3f364222d032eea6b245780e845ad213dab28cdd <ddc34a1b85505c919026ddc82fafdada9a160b15 || >=3f364222d032eea6b245780e845ad213dab28cdd <0db169a91381a473b7974021d1c02f8da72c5775 || >=3f364222d032eea6b245780e845ad213dab28cdd <d7b87adeb0eb539b9b824b101bb14fb01e41240b || >=3f364222d032eea6b245780e845ad213dab28cdd <57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52 || >=3f364222d032eea6b245780e845ad213dab28cdd <6557f1565d779851c4db9c488c49c05a47a6e72f | ffb5d1c5e3933b947fc7303ad68bf0c536d0c85e, ddc34a1b85505c919026ddc82fafdada9a160b15, 0db169a91381a473b7974021d1c02f8da72c5775, d7b87adeb0eb539b9b824b101bb14fb01e41240b, 57f7f6a0ad04a65c8a7a067b2f56cbbf2aec9e52, 6557f1565d779851c4db9c488c49c05a47a6e72f |
| Linux/Linuxgeneric | 5.18 | Not reported |
Published upstream
May 27, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Jun 25, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Jun 25, 2026
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.
Quoted source text, attributed separately from HOL analysis.