UBUNTU-CVE-2025-38591
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject narrower access to pointer ctx fields The following BPF program, simplified from a syzkaller repro, causes a kernel warning: r0 = *(u8 *)(r1 + 169); exit; With pointer field sk being at offset 168 in __sk_buff. This access is detected as a narrower read in bpf_skb_is_valid_access because it doesn't match offsetof(struct __sk_buff, sk). It is therefore allowed and later proceeds to bpf_convert_ctx_access. Note that for the "is_narrower_load" case in the convert_ctx_accesses(), the insn->off is aligned, so the cnt may not be 0 because it matches the offsetof(struct __sk_buff, sk) in the bpf_convert_ctx_access. However, the target_size stays 0 and the verifier errors with a kernel warning: verifier bug: error during ctx access conversion(1) This patch fixes that to return a proper "invalid bpf_context access off=X size=Y" error on the load instruction. The same issue affects multiple other fields in context structures that allow narrow access. Some other non-affected fields (for sk_msg, sk_lookup, and sockopt) were also changed to use bpf_ctx_range_ptr for consistency. Note this syzkaller crash was reported in the "Closes" link below, which used to be about a different bug, fixed in commit fce7bd8e385a ("bpf/verifier: Handle BPF_LOAD_ACQ instructions in insn_def_regno()"). Because syzbot somehow confused the two bugs, the new crash and repro didn't get reported to the mailing list.
02 / AFFECTED SOFTWARE
Affected packages
11 explicit affected versions
53 explicit affected versions
116 explicit affected versions
82 explicit affected versions
50 explicit affected versions
6 explicit affected versions
12 explicit affected versions
19 explicit affected versions
10 explicit affected versions
6 explicit affected versions
92 explicit affected versions
24 explicit affected versions
77 explicit affected versions
77 explicit affected versions
91 explicit affected versions
80 explicit affected versions
72 explicit affected versions
10 explicit affected versions
34 explicit affected versions
26 explicit affected versions
84 explicit affected versions
7 explicit affected versions
79 explicit affected versions
38 explicit affected versions
13 explicit affected versions
85 explicit affected versions
41 explicit affected versions
35 explicit affected versions
44 explicit affected versions
42 explicit affected versions
18 explicit affected versions
36 explicit affected versions
118 explicit affected versions
64 explicit affected versions
43 explicit affected versions
120 explicit affected versions
13 explicit affected versions
4 explicit affected versions
23 explicit affected versions
49 explicit affected versions
124 explicit affected versions
1 explicit affected versions
1 explicit affected versions
21 explicit affected versions
9 explicit affected versions
16 explicit affected versions
10 explicit affected versions
76 explicit affected versions
45 explicit affected versions
8 explicit affected versions
7 explicit affected versions
12 explicit affected versions
11 explicit affected versions
111 explicit affected versions
7 explicit affected versions
12 explicit affected versions
14 explicit affected versions
10 explicit affected versions
1 explicit affected versions
7 explicit affected versions
13 explicit affected versions
104 explicit affected versions
12 explicit affected versions
105 explicit affected versions
12 explicit affected versions
38 explicit affected versions
38 explicit affected versions
16 explicit affected versions
25 explicit affected versions
31 explicit affected versions
10 explicit affected versions
37 explicit affected versions
10 explicit affected versions
13 explicit affected versions
37 explicit affected versions
3 explicit affected versions
10 explicit affected versions
11 explicit affected versions
59 explicit affected versions
1 explicit affected versions
26 explicit affected versions
8 explicit affected versions
13 explicit affected versions
32 explicit affected versions
1 explicit affected versions
29 explicit affected versions
111 explicit affected versions
13 explicit affected versions
12 explicit affected versions
89 explicit affected versions
38 explicit affected versions
38 explicit affected versions
1 explicit affected versions
100 explicit affected versions
84 explicit affected versions
47 explicit affected versions
33 explicit affected versions
23 explicit affected versions
53 explicit affected versions
10 explicit affected versions
17 explicit affected versions
16 explicit affected versions
11 explicit affected versions
5 explicit affected versions
12 explicit affected versions
7 explicit affected versions
12 explicit affected versions
138 explicit affected versions
5 explicit affected versions
69 explicit affected versions
132 explicit affected versions
85 explicit affected versions
154 explicit affected versions
10 explicit affected versions
26 explicit affected versions
35 explicit affected versions
1 explicit affected versions
61 explicit affected versions
33 explicit affected versions
44 explicit affected versions
11 explicit affected versions
13 explicit affected versions
43 explicit affected versions
139 explicit affected versions
78 explicit affected versions
16 explicit affected versions
83 explicit affected versions
47 explicit affected versions
116 explicit affected versions
3 explicit affected versions
132 explicit affected versions
93 explicit affected versions
1 explicit affected versions
7 explicit affected versions
2 explicit affected versions
51 explicit affected versions
92 explicit affected versions
18 explicit affected versions
39 explicit affected versions
12 explicit affected versions
66 explicit affected versions
72 explicit affected versions
27 explicit affected versions
58 explicit affected versions
121 explicit affected versions
1 explicit affected versions
1 explicit affected versions
98 explicit affected versions
40 explicit affected versions
8 explicit affected versions
49 explicit affected versions
5 explicit affected versions
3 explicit affected versions
8 explicit affected versions
1 explicit affected versions
10 explicit affected versions
7 explicit affected versions
43 explicit affected versions
13 explicit affected versions
110 explicit affected versions
13 explicit affected versions
72 explicit affected versions
7 explicit affected versions
140 explicit affected versions
8 explicit affected versions
94 explicit affected versions
10 explicit affected versions
12 explicit affected versions
9 explicit affected versions
31 explicit affected versions
108 explicit affected versions
80 explicit affected versions
56 explicit affected versions
44 explicit affected versions
16 explicit affected versions
3 explicit affected versions
13 explicit affected versions
26 explicit affected versions
45 explicit affected versions
37 explicit affected versions
48 explicit affected versions
14 explicit affected versions
38 explicit affected versions
167 explicit affected versions
9 explicit affected versions
11 explicit affected versions
36 explicit affected versions
17 explicit affected versions
85 explicit affected versions
8 explicit affected versions
7 explicit affected versions
121 explicit affected versions
4 explicit affected versions
74 explicit affected versions
1 explicit affected versions
1 explicit affected versions
1 explicit affected versions
83 explicit affected versions
73 explicit affected versions
73 explicit affected versions
13 explicit affected versions
43 explicit affected versions
77 explicit affected versions
119 explicit affected versions
10 explicit affected versions
8 explicit affected versions
42 explicit affected versions
88 explicit affected versions
14 explicit affected versions
4 explicit affected versions
78 explicit affected versions
11 explicit affected versions
1 explicit affected versions
69 explicit affected versions
123 explicit affected versions
16 explicit affected versions
37 explicit affected versions
73 explicit affected versions
03 / CONNECTIONS
Connected vulnerabilities
04 / EVIDENCE
Source records
In the Linux kernel, the following vulnerability has been resolved: bpf: Reject narrower access to pointer ctx fields The following BPF program, simplified from a syzkaller repro, causes a kernel warning: r0 = *(u8 *)(r1 + 169); exit; With pointer field sk being at offset 168 in __sk_buff. This access is detected as a narrower read in bpf_skb_is_valid_access because it doesn't match offsetof(struct __sk_buff, sk). It is therefore allowed and later proceeds to bpf_convert_ctx_access. Note that for the "is_narrower_load" case in the convert_ctx_accesses(), the insn->off is aligned, so the cnt may not be 0 because it matches the offsetof(struct __sk_buff, sk) in the bpf_convert_ctx_access. However, the target_size stays 0 and the verifier errors with a kernel warning: verifier bug: error during ctx access conversion(1) This patch fixes that to return a proper "invalid bpf_context access off=X size=Y" error on the load instruction. The same issue affects multiple other fields in context structures that allow narrow access. Some other non-affected fields (for sk_msg, sk_lookup, and sockopt) were also changed to use bpf_ctx_range_ptr for consistency. Note this syzkaller crash was reported in the "Closes" link below, which used to be about a different bug, fixed in commit fce7bd8e385a ("bpf/verifier: Handle BPF_LOAD_ACQ instructions in insn_def_regno()"). Because syzbot somehow confused the two bugs, the new crash and repro didn't get reported to the mailing list.
05 / REFERENCES
Further evidence
- https://git.kernel.org/linus/e09299225d5ba3916c91ef70565f7d2187e4cca0
- https://git.kernel.org/stable/c/202900ceeef67458c964c2af6e1427c8e533ea7c
- https://git.kernel.org/stable/c/e09299225d5ba3916c91ef70565f7d2187e4cca0
- https://ubuntu.com/security/CVE-2025-38591
- https://ubuntu.com/security/notices/USN-8162-1
- https://ubuntu.com/security/notices/USN-8180-1
- https://ubuntu.com/security/notices/USN-8180-2
- https://ubuntu.com/security/notices/USN-8180-3
- https://ubuntu.com/security/notices/USN-8180-4
- https://ubuntu.com/security/notices/USN-8180-5
- https://ubuntu.com/security/notices/USN-8180-6
- https://ubuntu.com/security/notices/USN-8186-1
- https://ubuntu.com/security/notices/USN-8187-1
- https://ubuntu.com/security/notices/USN-8188-1
- https://ubuntu.com/security/notices/USN-8243-1
- https://ubuntu.com/security/notices/USN-8275-1
- https://ubuntu.com/security/notices/USN-8278-1
- https://ubuntu.com/security/notices/USN-8278-2
- https://ubuntu.com/security/notices/USN-8289-1
- https://ubuntu.com/security/notices/USN-8289-2
- https://ubuntu.com/security/notices/USN-8296-1
- https://ubuntu.com/security/notices/USN-8296-2
- https://ubuntu.com/security/notices/USN-8297-1
- https://ubuntu.com/security/notices/USN-8393-1
- https://ubuntu.com/security/notices/USN-8440-1
- https://ubuntu.com/security/notices/USN-8499-1
- https://www.cve.org/CVERecord?id=CVE-2025-38591