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Vulnerabilities

Vulnerability · CVE-2026-99109

smb: client: reject SetEA requests that do not fit the request buffer

Published Oct 28, 2026 · catalog updated Nov 7, 2026 · BSI

Last checked Nov 7, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2026-99109. EPSS is 0.14%. Act only if a listed version of BSI is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
High7.8
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.14%
Remediation
Advisory link
Affected products
Debian:12 linux · Debian:13 linux · Debian:14 linux · Linux Kernel

In the Linux kernel, the following vulnerability has been resolved: smb: client: reject SetEA requests that do not fit the request buffer CIFSSMBSetEA() copies the caller's extended attribute value into the SMB request buffer without checking that it fits. The requirement is stated in the source but was never implemented: /*BB add length check to see if it would fit in negotiated SMB buffer size BB */ /* if (ea_value_len > buffer_size - 512 (enough for header)) */ if (ea_value_len) memcpy(parm_data->list.name + name_len + 1, ea_value, ea_value_len); The only bound applied on the way in is in cifs_xattr_set(): #define MAX_EA_VALUE_SIZE CIFSMaxBufSize ... if (size > MAX_EA_VALUE_SIZE) CIFSMaxBufSize is the full payload capacity of the buffer, so a value of exactly that size leaves no room for the SMB header, the TRANS2 parameter block, the fealist header and the EA name that are written ahead of it in the same object. SendReceive() already enforces the correct limit on this very length: if (in_len > CIFSMaxBufSize + MAX_CIFS_HDR_SIZE) but it is called after the copy has taken place. An unprivileged setxattr(2) on an SMB1 mount with a 250-byte name and a 16384-byte value writes 16384 bytes starting 345 bytes into a 16588-byte cifs_request object, ending 141 bytes past it: BUG: KASAN: slab-out-of-bounds in CIFSSMBSetEA+0xabc/0xde0 Write of size 16384 at addr ffff888003aa0159 by task init/68 __asan_memcpy+0x3c/0x60 CIFSSMBSetEA+0xabc/0xde0 cifs_xattr_set+0xd3a/0xff0 __vfs_setxattr+0x13e/0x1a0 The buggy address is located 345 bytes inside of allocated 16588-byte region Apply SendReceive()'s limit to the assembled request before the copy rather than after it, and widen the byte counters so the sum cannot wrap before it is tested. byte_count is also tested against U16_MAX, because it is stored in the 16-bit pSMB->ByteCount. That becomes reachable when CIFSMaxBufSize is raised at module load, where it may be set as high as 1024*127: with a 5-byte EA name and a 65521-byte val

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • Debian:12 linux6.1.106-1, 6.1.106-2, 6.1.106-3
  • Debian:13 linux6.12.100-1, 6.12.101-1, 6.12.105-1
  • Debian:14 linux6.12.100-1, 6.12.101-1, 6.12.105-1
  • Linux Kernel2.6.12 → 6.18.61; 6.19.0 → 7.2.13
  • Linux Kernel2.6.12 → 7.2.13

How to fix CVE-2026-99109

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2026-99109. EPSS is 0.14%. Act only if a listed version of BSI is installed.

Which versions are affected?

Compare what you have installed with Kernel 2.6.12 → 6.18.61; 6.19.0 → 7.2.13; Kernel 2.6.12 → 7.2.13. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.14%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Technology hubs

Debian security

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Oct 29, 2026 · BSI CERT-Bund

    Detected

    CVE-2026-99109 is listed by Linux Kernel: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff.

  2. Nov 1, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 7.2.13

  3. Nov 1, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 7.2.13

  4. Nov 1, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    In the Linux kernel, the following vulnerability has been resolved: smb: client: reject SetEA requests that do not fit the request buffer CIFSSMBSetEA() copies the caller's extended attribute value into the SMB request buffer without checking that it fits. The requirement is stated in the source but was never implemented: /*BB add length check to see if it would fit in negotiated SMB buffer size B

  5. Nov 1, 2026 · Trivy Vulnerability DB

    Updated

    In the Linux kernel, the following vulnerability has been resolved: smb: client: reject SetEA requests that do not fit the request buffer CIFSSMBSetEA() copies the caller's extended attribute value into the SMB request buffer without checking that it fits. The requirement is stated in the source but was never implemented: /*BB add length check to see if it would fit in negotiated SMB buffer size B

  6. Nov 7, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 6.18.61; Kernel fixed in 7.2.13

  7. Nov 7, 2026 · OpenSSF OSV / OSV Scanner

    Fix available

    Kernel fixed in 6.18.61; 6.19.0

  8. Nov 7, 2026 · OpenSSF OSV / OSV Scanner

    Updated

    In the Linux kernel, the following vulnerability has been resolved: smb: client: reject SetEA requests that do not fit the request buffer CIFSSMBSetEA() copies the caller's extended attribute value into the SMB request buffer without checking that it fits. The requirement is stated in the source but was never implemented: /*BB add length check to see if it would fit in negotiated SMB buffer size B

Sources

  • BSI CERT-BundGovernment advisoryCVE-2026-99109

    Linux Kernel: Mehrere Schwachstellen ermöglichen nicht spezifizierten Angriff

    wid.cert-bund.de
  • CVE.orgVulnerability recordCVE-2026-99109

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2026-99109

    30-day exploitation probability 0.14%

    first.org
  • OpenSSF OSV / OSV ScannerPackage advisoryCVE-2026-99109

    smb: client: reject SetEA requests that do not fit the request buffer

    osv.dev
  • Tenable CVE DatabaseVulnerability recordCVE-2026-99109

    In the Linux kernel, the following vulnerability has been resolved: smb: client: reject SetEA requests that do not fit the request buffer CIFSSMBSetEA() copies the caller's extended attribute value into the SMB request buffer without checking that it fits. The requirement is stated in the source but was never implemented: /*BB add length check to see if it would fit in negotiated SMB buffer size B

    tenable.com
  • Trivy Vulnerability DBPackage advisoryDEBIAN-CVE-2026-99109

    In the Linux kernel, the following vulnerability has been resolved: smb: client: reject SetEA requests that do not fit the request buffer CIFSSMBSetEA() copies the caller's extended attribute value into the SMB request buffer without checking that it fits. The requirement is stat

    osv.dev

References

Freshness

Last verified in this catalog Nov 7, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSNov 7, 2026
  • OpenSSF OSV / OSV ScannerNov 7, 2026
  • Trivy Vulnerability DBNov 1, 2026
  • Tenable CVE DatabaseNov 1, 2026
  • CVE.orgOct 30, 2026
  • BSI CERT-BundOct 30, 2026