{"cve":"CVE-2024-57878","nvd":{"published":"2025-01-11T15:15:08.190","modified":"2026-06-17T08:14:07.843","status":"Modified","description":"In the Linux kernel, the following vulnerability has been resolved:\n\narm64: ptrace: fix partial SETREGSET for NT_ARM_FPMR\n\nCurrently fpmr_set() doesn't initialize the temporary 'fpmr' variable,\nand a SETREGSET call with a length of zero will leave this\nuninitialized. Consequently an arbitrary value will be written back to\ntarget->thread.uw.fpmr, potentially leaking up to 64 bits of memory from\nthe kernel stack. The read is limited to a specific slot on the stack,\nand the issue does not provide a write mechanism.\n\nFix this by initializing the temporary value before copying the regset\nfrom userspace, as for other regsets (e.g. NT_PRSTATUS, NT_PRFPREG,\nNT_ARM_SYSTEM_CALL). In the case of a zero-length write, the existing\ncontents of FPMR will be retained.\n\nBefore this patch:\n\n| # ./fpmr-test\n| Attempting to write NT_ARM_FPMR::fpmr = 0x900d900d900d900d\n| SETREGSET(nt=0x40e, len=8) wrote 8 bytes\n|\n| Attempting to read NT_ARM_FPMR::fpmr\n| GETREGSET(nt=0x40e, len=8) read 8 bytes\n| Read NT_ARM_FPMR::fpmr = 0x900d900d900d900d\n|\n| Attempting to write NT_ARM_FPMR (zero length)\n| SETREGSET(nt=0x40e, len=0) wrote 0 bytes\n|\n| Attempting to read NT_ARM_FPMR::fpmr\n| GETREGSET(nt=0x40e, len=8) read 8 bytes\n| Read NT_ARM_FPMR::fpmr = 0xffff800083963d50\n\nAfter this patch:\n\n| # ./fpmr-test\n| Attempting to write NT_ARM_FPMR::fpmr = 0x900d900d900d900d\n| SETREGSET(nt=0x40e, len=8) wrote 8 bytes\n|\n| Attempting to read NT_ARM_FPMR::fpmr\n| GETREGSET(nt=0x40e, len=8) read 8 bytes\n| Read NT_ARM_FPMR::fpmr = 0x900d900d900d900d\n|\n| Attempting to write NT_ARM_FPMR (zero length)\n| SETREGSET(nt=0x40e, len=0) wrote 0 bytes\n|\n| Attempting to read NT_ARM_FPMR::fpmr\n| GETREGSET(nt=0x40e, len=8) read 8 bytes\n| Read NT_ARM_FPMR::fpmr = 0x900d900d900d900d","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:H","score":6.1},"cwes":["CWE-908"],"references":["https://git.kernel.org/stable/c/8ab73c34e3c5b580721696665eabd799346bc50b","https://git.kernel.org/stable/c/f5d71291841aecfe5d8435da2dfa7f58ccd18bc8"],"products":["linux:linux_kernel"],"source":"nvd","synced_at":"2026-10-19T21:58:20.756570362+00:00"},"epss":{"cve":"CVE-2024-57878","score":0.00185,"percentile":0.08074,"date":"2026-10-31"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}