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TI-2026-79487 Aliases CVE-2026-115505GHSA-jfx5-c9g5-vf27

Integer overflow in libsmb2 DCE/RPC NDR decoder lets servers corrupt heap

Priority HIGH 71CWE-190Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
Passive
Attack complexity
Low
Attack requirements
None
Impact type
—
Confidentiality · integrity · availability
Low · Low · High
Fix status
Fixed

Attack profile from CVSS 4.0 · CNA. Fix status from CNA.

Summary

libsmb2 before 6.3 contains integer overflow flaws in the DCE/RPC NDR decoder in lib/dcerpc.c that allow heap out-of-bounds reads and writes. A malicious SMB server or machine-in-the-middle on unsigned connections can send crafted NetrShareEnum replies with wrapping actual_count or max_count values when clients call smb2_share_enum_async(), corrupting heap memory (CWE-190). A public proof of concept is linked in the references.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

Description from the CNA

libsmb2 before 6.3 contains integer overflow vulnerabilities in the DCE/RPC NDR decoder in lib/dcerpc.c that allow heap out-of-bounds reads and writes. A malicious SMB server or machine-in-the-middle on unsigned connections can send crafted NetrShareEnum replies with wrapping actual_count or max_count values when clients call smb2_share_enum_async(), corrupting heap memory.

Why it matters now

Exploitation Proof of concept CISA SSVC · not in CISA KEV
EPSS 0.00207 10th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by the CNA
Fix Fixed libsmb2 (sahlberg): 6.3

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Poc
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
sahlberglibsmb2before 6.36.3Patch availableCNA
  • libsmb2 Vendorsahlberg Affected before 6.3 Fixed in 6.3 Patch available CNA

Remediation

Upgrade libsmb2 to version 6.3.

Written with Claude Haiku 5.5 from the sources below · 2026-10-29

  • Fix · CNA libsmb2 (sahlberg) Fixed in 6.3

Timeline

  1. 2026-10-22 Threatist record created from CVE-2026-115505
  2. 2026-10-22 Alias added: GHSA-jfx5-c9g5-vf27
  3. 2026-10-23 Priority changed: MEDIUM → LOW
  4. 2026-10-29 CISA SSVC decision points changed
  5. 2026-10-29 Priority changed: LOW → HIGH

References

Exploit 1

Patch 1

Other 3

  • TI-2026-74155 Integer underflow in libsmb2 decode_acl causes heap over-read CVSS 4.0HIGH 7.1
  • TI-2026-74154 libsmb2 Heap Out-of-Bounds Read via File System Info Decoders CVSS 4.0HIGH 7.1
  • TI-2026-74153 Heap out-of-bounds read in libsmb2 lets SMB servers crash clients CVSS 4.0HIGH 7.1
  • TI-2026-41697 Integer underflow in sahlberg libnfs CVSS 3.1HIGH 7.1
  • TI-2026-38717 libnfs through 6.0.2 before 55c18ea does not validate a string size, leading to an… CVSS 3.1HIGH 7.1
  • TI-2026-70831 Out-of-bounds write in libnfs ZDR decoding CVSS 3.1HIGH 7.1

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences