high CVSS 7.8

CVE-2024-50203·Kernel vulnerability

In the Linux kernel, the following vulnerability has been resolved: bpf, arm64: Fix address emission with tag-based KASAN enabled When BPF_TRAMP_F_CALL_ORIG is enabled, the address of a bpf_tramp_image struct on the stack is passed during the size calculation pass and an address on the heap is passed during code generation. This may cause a heap buffer overflow if the heap address is tagged because emit_a64_mov_i64() will emit longer code than it did during the size calculation pass. The same problem could occur without tag-based KASAN if one of the 16-bit words of the stack address happened to be all-ones during the size calculation pass. Fix the problem by assuming the worst case (4 instructions) when calculating the size of the bpf_tramp_image address emission.

Severity
high
Software
Kernel
Fixed in
6.11.6
Published
2024-11-08

Affected versions

From: 6.11

Until: 6.11.6

Fixed in: 6.11.6

How to fix this CVE

Update your Linux kernel to version 6.11.6 or later to resolve a heap buffer overflow vulnerability in the ARM64 BPF trampoline code generation when tag-based KASAN is enabled. This vulnerability could allow local privilege escalation through improperly calculated instruction emission during BPF program compilation. Apply the kernel update immediately and reboot your system.

sudo dnf update kernel kernel-devel && sudo reboot

Defensia detects this vulnerability

How to check if you are affected

  1. Run 'uname -r' to check your current kernel version and confirm if it falls within the vulnerable range (6.11.0 to 6.11.5)
  2. Check if BPF and KASAN are enabled in your kernel config: grep -i 'CONFIG_BPF\|CONFIG_KASAN' /boot/config-$(uname -r)
  3. Monitor dmesg for heap corruption warnings or BPF-related errors: dmesg | grep -i 'heap\|bpf\|overflow\|kasan'
  4. After patching, verify the new kernel version with 'uname -r' and confirm it reports version 6.11.6 or higher

FAQ

What is CVE-2024-50203?

This vulnerability is a heap buffer overflow in the Linux kernel's ARM64 BPF code generator that occurs when tag-based KASAN is enabled, caused by incorrect size calculation during instruction emission for BPF trampoline function calls.

Is CVE-2024-50203 being actively exploited?

No, there are currently no public exploits or active exploitation reports for this vulnerability in the wild according to CISA threat data.

What versions of Kernel are affected by CVE-2024-50203?

Linux kernel versions 6.11.0 through 6.11.5 are vulnerable; version 6.11.6 and later contain the fix.

How do I check if my server is vulnerable to CVE-2024-50203?

Run 'uname -r' to get your kernel version. If it returns a version between 6.11.0 and 6.11.5 inclusive, your system is vulnerable.

Does Defensia detect CVE-2024-50203?

Yes — Defensia's CVE advisory scanner compares installed package versions against the NVD database. If Kernel is installed on a monitored server, CVE-2024-50203 will appear in your dashboard with remediation steps.

Related Kernel CVEs

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CVE-2026-64385CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_ioctl() replay A response-bearing attempt can return a replayable error and free its response buffer. If SMB2_ioctl_init() fails before the next send, cleanup retains the previous buffer type and frees that response again. Reset response bookkeeping before each attempt to prevent the stale free.
CVE-2026-64391CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: ksmbd: use opener credentials for ADS I/O Alternate data streams are stored as xattrs. Unlike regular file I/O, their read and write paths therefore call VFS xattr helpers which recheck inode permissions and LSM policy using the current task credentials. Run ADS I/O with the credentials captured when the SMB handle was opened.
CVE-2026-64383CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: smb: client: fix double-free in SMB2_flush() replay SMB2_flush() keeps its response buffer bookkeeping across replay attempts. If a replayable flush response is received and the retry then fails before cifs_send_recv() stores a replacement response, flush_exit will free the stale response pointer a second time. Reinitialize resp_buftype and rsp_iov at the top of the replay loop so cleanup only acts on response state produced by the current attempt. This fixes a double-free without changing replay handling for successful requests.
CVE-2026-53176CVSS 9.8In the Linux kernel, the following vulnerability has been resolved: IB/isert: Reject login PDUs shorter than ISER_HEADERS_LEN In drivers/infiniband/ulp/isert/ib_isert.c, isert_login_recv_done() computes the login request payload length as wc->byte_len minus ISER_HEADERS_LEN with no lower bound, and login_req_len is a signed int. A remote iSER initiator can post a login Send work request carrying fewer than ISER_HEADERS_LEN (76) bytes, so the subtraction underflows and login_req_len becomes negative. isert_rx_login_req() then reads that negative length back into a signed int, takes size = min(rx_buflen, MAX_KEY_VALUE_PAIRS), and because the min() is signed it keeps the negative value; the value is then passed as the memcpy() length and sign-extended to a multi-gigabyte size_t. The copy into the 8192-byte login->req_buf runs far out of bounds and faults, crashing the target node. The login phase precedes iSCSI authentication, so no credentials are required to reach this path. Reject any login PDU shorter than ISER_HEADERS_LEN before the subtraction, mirroring the existing early return on a failed work completion, so login_req_len can never go negative. The upper bound was already safe: a posted login buffer cannot deliver more than ISER_RX_PAYLOAD_SIZE, so the difference stays at or below MAX_KEY_VALUE_PAIRS and the existing min() clamps it; only the missing lower bound needs to be added.

References

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