{"id":"CVE-2021-46974","title":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix masking negation logic upon negative dst register\n\nThe negation logic for the case where the off_reg is sitting in the\ndst register is not correct given then w…","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix masking negation logic upon negative dst register\n\nThe negation logic for the case where the off_reg is sitting in the\ndst register is not correct given then w…","severity":"high","cvss":7.1,"cvssVector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H","vendor":"linux","product":"linux_kernel","affected":["linux_kernel >= 4.14.113, < 4.14.233","linux_kernel >= 4.19.19, < 4.19.190","linux_kernel >= 5.0, < 5.4.117","linux_kernel >= 5.5, < 5.10.35","linux_kernel >= 5.11, < 5.11.19","linux_kernel >= 5.12, < 5.12.2"],"patched":["linux_kernel 5.12.2"],"published":"2024-02-27","updated":"2026-08-04","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2021-46974","references":[{"url":"https://git.kernel.org/stable/c/0e2dfdc74a7f4036127356d42ea59388f153f42c","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/2cfa537674cd1051a3b8111536d77d0558f33d5d","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/4d542ddb88fb2f39bf7f14caa2902f3e8d06f6ba","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/53e0db429b37a32b8fc706d0d90eb4583ad13848","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/6eba92a4d4be8feb4dc33976abac544fa99d6ecc","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/7cf64d8679ca1cb20cf57d6a88bfee79a0922a66","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/b9b34ddbe2076ade359cd5ce7537d5ed019e9807","label":"416baaa9-dc9f-4396-8d5f-8c081fb06d67"},{"url":"https://git.kernel.org/stable/c/0e2dfdc74a7f4036127356d42ea59388f153f42c","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/2cfa537674cd1051a3b8111536d77d0558f33d5d","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/4d542ddb88fb2f39bf7f14caa2902f3e8d06f6ba","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/53e0db429b37a32b8fc706d0d90eb4583ad13848","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/6eba92a4d4be8feb4dc33976abac544fa99d6ecc","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/7cf64d8679ca1cb20cf57d6a88bfee79a0922a66","label":"af854a3a-2127-422b-91ae-364da2661108"},{"url":"https://git.kernel.org/stable/c/b9b34ddbe2076ade359cd5ce7537d5ed019e9807","label":"af854a3a-2127-422b-91ae-364da2661108"}],"tags":["nvd"],"epss":0.00247,"epssPercentile":0.16316,"ingestedAt":"2026-08-04T10:39:38.704Z","slug":"CVE-2021-46974","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fix masking negation logic upon negative dst register\n\nThe negation logic for the case where the off_reg is sitting in the\ndst register is not correct given then we cannot just invert the add\nto a sub or vice versa. As a fix, perform the final bitwise and-op\nunconditionally into AX from the off_reg, then move the pointer from\nthe src to dst and finally use AX as the source for the original\npointer arithmetic operation such that the inversion yields a correct\nresult. The single non-AX mov in between is possible given constant\nblinding is retaining it as it's not an immediate based operation.\n\n## Affected\n\n- `linux_kernel >= 4.14.113, < 4.14.233`\n- `linux_kernel >= 4.19.19, < 4.19.190`\n- `linux_kernel >= 5.0, < 5.4.117`\n- `linux_kernel >= 5.5, < 5.10.35`\n- `linux_kernel >= 5.11, < 5.11.19`\n- `linux_kernel >= 5.12, < 5.12.2`\n\n## Remediation\n\nUpgrade past the affected range:\n\n- `linux_kernel 5.12.2`","depth":"twilight","depthScore":39,"depthScoreParts":{"impact":39.1,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}