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CVE-2026-26825

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS...

5.3 MediumFix available

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.

Attack profile

How easy it is to exploit

Attack vector
Network
Complexity
Low
Privileges needed
None
User interaction
None

What an attacker can affect

Confidentiality
Low
Integrity
None
Availability
None

Exploit likelihood

0.24%Up 0.2 points since Jun 4, 2026
90%50%10%1%

What each source reports

NVD Score used 5.3

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.

Record
CVE-2026-26825
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-908
Updated
2026-11-02
CVE List 5.3

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.

Record
CVE-2026-26825
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-908
Updated
2026-11-02
EUVDEUVD-2026-34179 5.3

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.

Record
EUVD-2026-34179
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Updated
2026-11-02
GitHub AdvisoriesGHSA-48jr-3rh3-95w6 5.3

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS...

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.

Record
GHSA-48jr-3rh3-95w6
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Weakness
CWE-908
Updated
2026-11-02
OSV 5.3

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.

Record
CVE-2026-26825
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Updated
2026-11-02
OSVDEBIAN-CVE-2026-26825 5.3

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.

Record
DEBIAN-CVE-2026-26825
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Updated
2026-11-02
OSVUBUNTU-CVE-2026-26825 5.3

A use-of-uninitialized memory vulnerability exists in libxls 1.6.3 when parsing malformed XLS files. The issue is reachable via xls_parseWorkBook() and is triggered by uninitialized heap memory originating from the OLE layer (ole2_read). The flaw is detectable with MemorySanitizer (MSAN) and can lead to undefined behavior, incorrect parsing logic, or potential information disclosure.

Record
UBUNTU-CVE-2026-26825
CVSS 3.1
5.3 MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N
Updated
2026-11-02
OSVopenSUSE-SU-2026:12110-1 No score

libxls-devel-1.6.4-1.1 on GA media

These are all security issues fixed in the libxls-devel-1.6.4-1.1 package on the GA media of openSUSE Tumbleweed.

Record
openSUSE-SU-2026:12110-1
Updated
2026-11-02
OSVopenSUSE-SU-2026:22128-1 No score

Security update for libxls

This update for libxls fixes the following issues:

Changes in libxls:

Update to release 1.6.4:

  • Fix use of uninitialized memory in OLE parsing [boo#1267687, CVE-2026-26825]
  • Fix use of uninitialized memory in read_MSAT [boo#1267608, CVE-2026-26824]
  • Fix use of uninitialized memory in xls_parseWorkBook
  • Fix out-of-bounds reads in the formula dumper
  • Handle allocation failures in OLE, workbook and string code
  • Read SummaryInformation streams at their real size
  • Keep full precision when converting numeric cells to strings
  • Fix "creation of UTF-8 locale failed" in xls2csv

Update to release 1.6.3:

  • Fix style record size check on big-endian systems
  • Fix header include in C++ mode
  • Fix buffer overflows when parsing style records
  • Fix infinite loop with self-referencing sectors
Record
openSUSE-SU-2026:22128-1
Updated
2026-11-02

Affected products

Affected packages

Affected packages
PackageAffectedFixed
r-cran-readxl
Debian:12
All versions, plus listed versions
1.4.2-11.4.3-11.4.4-11.4.5-11.5.0-11.5.0.1-11.6.0-1
None known
r-cran-readxl
Debian:13
All versions, plus listed versions
1.4.5-11.5.0-11.5.0.1-11.6.0-1
None known
r-cran-readxl
Debian:14
before 1.6.0-1, plus listed versions
1.4.5-11.5.0-11.5.0.1-1
1.6.0-1
r-cran-readxl
Ubuntu:16.04:LTS
All versions, plus listed versions
0.1.0-1
None known
r-cran-readxl
Ubuntu:18.04:LTS
All versions, plus listed versions
1.0.0-1build11.0.0-2
None known
r-cran-readxl
Ubuntu:20.04:LTS
All versions, plus listed versions
1.3.1-21.3.1-2build1
None known
r-cran-readxl
Ubuntu:22.04:LTS
All versions, plus listed versions
1.3.1-2build2
None known
r-cran-readxl
Ubuntu:24.04:LTS
All versions, plus listed versions
1.4.3-1
None known
r-cran-readxl
Ubuntu:25.10
All versions, plus listed versions
1.4.5-1
None known
r-cran-readxl
Ubuntu:26.10
All versions, plus listed versions
1.4.5-11.5.0-1
None known
r-cran-readxl
Ubuntu:26.04:LTS
All versions, plus listed versions
1.4.5-1
None known
libxls
openSUSE:Tumbleweed
From an advisory covering 2 CVEs
before 1.6.4-1.1
1.6.4-1.1
libxls
openSUSE:Leap 16.0
From an advisory covering 2 CVEs
before 1.6.4-bp160.1.1
1.6.4-bp160.1.1

History

History
RecordedChangedSources
affected, facts
first indexedCVE List, EUVD, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2026-26825 is a medium vulnerability (CVSS 5.3) in Libxls Project Libxls, published June 3, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.24%, the 15th percentile. Fixed in r-cran-readxl 1.6.0-1.

References

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