#1139808 r-cran-readxl: CVE-2026-26824 CVE-2026-26825

Package:
src:r-cran-readxl
Source:
src:r-cran-readxl
Submitter:
Moritz Mühlenhoff
Date:
2026-06-24 13:15:01 UTC
Severity:
normal
Tags:
#1139808#5
Date:
2026-06-12 14:16:12 UTC
From:
To:
Hi,

The following vulnerabilities were published for libxls, which is
part of r-cran-readxl:

CVE-2026-26824[0]:
| libxls through version 1.6.3 contains a use of uninitialized memory
| vulnerability in the OLE container parser. Memory allocated for the
| Master Sector Allocation Table (MSAT) in read_MSAT() is not fully
| initialized before being consumed by ole2_validate_sector_chain(),
| which may result in application crashes or potential information
| disclosure when processing a crafted XLS file

https://github.com/libxls/libxls/issues/156


CVE-2026-26825[1]:
| 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.

https://github.com/libxls/libxls/issues/155


If you fix the vulnerabilities please also make sure to include the
CVE (Common Vulnerabilities & Exposures) ids in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-26824
https://www.cve.org/CVERecord?id=CVE-2026-26824
[1] https://security-tracker.debian.org/tracker/CVE-2026-26825
https://www.cve.org/CVERecord?id=CVE-2026-26825

Please adjust the affected versions in the BTS as needed.

#1139808#10
Date:
2026-06-12 15:18:11 UTC
From:
To:
Hi Jenny,

Just like a few years ago, there appears to a (pair of) new CVE(s) for
readxl.

Can I assume you will deal with this at the CRAN package level? The GH issues
linked below were opened quite some time ago, and there is no follow-up from
Evan I can see :-/  Have you been in contact with him?

Cheers, Dirk

On 12 June 2026 at 16:16, Moritz Mühlenhoff wrote:
| Source: r-cran-readxl
| X-Debbugs-CC: team@security.debian.org
| Severity: important
| Tags: security
|
| Hi,
|
| The following vulnerabilities were published for libxls, which is
| part of r-cran-readxl:
|
| CVE-2026-26824[0]:
| | libxls through version 1.6.3 contains a use of uninitialized memory
| | vulnerability in the OLE container parser. Memory allocated for the
| | Master Sector Allocation Table (MSAT) in read_MSAT() is not fully
| | initialized before being consumed by ole2_validate_sector_chain(),
| | which may result in application crashes or potential information
| | disclosure when processing a crafted XLS file
|
| https://github.com/libxls/libxls/issues/156
|
|
| CVE-2026-26825[1]:
| | 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.
|
| https://github.com/libxls/libxls/issues/155
|
|
| If you fix the vulnerabilities please also make sure to include the
| CVE (Common Vulnerabilities & Exposures) ids in your changelog entry.
|
| For further information see:
|
| [0] https://security-tracker.debian.org/tracker/CVE-2026-26824
|     https://www.cve.org/CVERecord?id=CVE-2026-26824
| [1] https://security-tracker.debian.org/tracker/CVE-2026-26825
|     https://www.cve.org/CVERecord?id=CVE-2026-26825
|
| Please adjust the affected versions in the BTS as needed.

#1139808#11
Date:
2026-06-12 17:46:25 UTC
From:
To:
Hi Dirk,

I do follow the libxls repo in a very passive manner, so presumably my
eyeballs have been exposed to this.

But, no, I haven't got a true open issue about it, in the literal or
metaphorical sense, nor have I corresponded with Evan.

Will you open a readxl issue stating that it's creating issues for you
on Debian? That at least puts it on my radar.

Thanks, Jenny

#1139808#16
Date:
2026-06-12 17:54:06 UTC
From:
To:
On 12 June 2026 at 10:46, Jenny Bryan wrote:
| Hi Dirk,
|
| I do follow the libxls repo in a very passive manner, so presumably my
| eyeballs have been exposed to this.
|
| But, no, I haven't got a true open issue about it, in the literal or
| metaphorical sense, nor have I corresponded with Evan.
|
| Will you open a readxl issue stating that it's creating issues for you
| on Debian? That at least puts it on my radar.

Done, as you likely saw. Now at https://github.com/tidyverse/readxl/issues/795

Dirk

| Thanks, Jenny
|
| On Fri, Jun 12, 2026 at 8:18 AM Dirk Eddelbuettel <edd@debian.org> wrote:
| >
| >
| > Hi Jenny,
| >
| > Just like a few years ago, there appears to a (pair of) new CVE(s) for
| > readxl.
| >
| > Can I assume you will deal with this at the CRAN package level? The GH issues
| > linked below were opened quite some time ago, and there is no follow-up from
| > Evan I can see :-/  Have you been in contact with him?
| >
| > Cheers, Dirk
| >
| > On 12 June 2026 at 16:16, Moritz Mühlenhoff wrote:
| > | Source: r-cran-readxl
| > | X-Debbugs-CC: team@security.debian.org
| > | Severity: important
| > | Tags: security
| > |
| > | Hi,
| > |
| > | The following vulnerabilities were published for libxls, which is
| > | part of r-cran-readxl:
| > |
| > | CVE-2026-26824[0]:
| > | | libxls through version 1.6.3 contains a use of uninitialized memory
| > | | vulnerability in the OLE container parser. Memory allocated for the
| > | | Master Sector Allocation Table (MSAT) in read_MSAT() is not fully
| > | | initialized before being consumed by ole2_validate_sector_chain(),
| > | | which may result in application crashes or potential information
| > | | disclosure when processing a crafted XLS file
| > |
| > | https://github.com/libxls/libxls/issues/156
| > |
| > |
| > | CVE-2026-26825[1]:
| > | | 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.
| > |
| > | https://github.com/libxls/libxls/issues/155
| > |
| > |
| > | If you fix the vulnerabilities please also make sure to include the
| > | CVE (Common Vulnerabilities & Exposures) ids in your changelog entry.
| > |
| > | For further information see:
| > |
| > | [0] https://security-tracker.debian.org/tracker/CVE-2026-26824
| > |     https://www.cve.org/CVERecord?id=CVE-2026-26824
| > | [1] https://security-tracker.debian.org/tracker/CVE-2026-26825
| > |     https://www.cve.org/CVERecord?id=CVE-2026-26825
| > |
| > | Please adjust the affected versions in the BTS as needed.
| >
| > --
| > Dirk Eddelbuettel | edd@debian.org | http://dirk.eddelbuettel.com
| >
| > Support my Tour de Shore 2026 ride benefiting Maywood Fine Arts! More info at
| > https://dirk.eddelbuettel.com/blog/2026/04/03#sponsor_tour_de_shore_2026

#1139808#21
Date:
2026-06-24 13:14:19 UTC
From:
To:
On 12 June 2026 at 12:54, Dirk Eddelbuettel wrote:
|
| On 12 June 2026 at 10:46, Jenny Bryan wrote:
| | Hi Dirk,
| |
| | I do follow the libxls repo in a very passive manner, so presumably my
| | eyeballs have been exposed to this.
| |
| | But, no, I haven't got a true open issue about it, in the literal or
| | metaphorical sense, nor have I corresponded with Evan.
| |
| | Will you open a readxl issue stating that it's creating issues for you
| | on Debian? That at least puts it on my radar.
|
| Done, as you likely saw. Now at https://github.com/tidyverse/readxl/issues/795

For the Debian bug tracker record, there has been zero follow-up upstream at
readxl.  Just how there has been zero follow-up at its upstream, libxls,
since the issue were opened there.

Not great.

Dirk

| Dirk
|
| | Thanks, Jenny
| |
| | On Fri, Jun 12, 2026 at 8:18 AM Dirk Eddelbuettel <edd@debian.org> wrote:
| | >
| | >
| | > Hi Jenny,
| | >
| | > Just like a few years ago, there appears to a (pair of) new CVE(s) for
| | > readxl.
| | >
| | > Can I assume you will deal with this at the CRAN package level? The GH issues
| | > linked below were opened quite some time ago, and there is no follow-up from
| | > Evan I can see :-/  Have you been in contact with him?
| | >
| | > Cheers, Dirk
| | >
| | > On 12 June 2026 at 16:16, Moritz Mühlenhoff wrote:
| | > | Source: r-cran-readxl
| | > | X-Debbugs-CC: team@security.debian.org
| | > | Severity: important
| | > | Tags: security
| | > |
| | > | Hi,
| | > |
| | > | The following vulnerabilities were published for libxls, which is
| | > | part of r-cran-readxl:
| | > |
| | > | CVE-2026-26824[0]:
| | > | | libxls through version 1.6.3 contains a use of uninitialized memory
| | > | | vulnerability in the OLE container parser. Memory allocated for the
| | > | | Master Sector Allocation Table (MSAT) in read_MSAT() is not fully
| | > | | initialized before being consumed by ole2_validate_sector_chain(),
| | > | | which may result in application crashes or potential information
| | > | | disclosure when processing a crafted XLS file
| | > |
| | > | https://github.com/libxls/libxls/issues/156
| | > |
| | > |
| | > | CVE-2026-26825[1]:
| | > | | 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.
| | > |
| | > | https://github.com/libxls/libxls/issues/155
| | > |
| | > |
| | > | If you fix the vulnerabilities please also make sure to include the
| | > | CVE (Common Vulnerabilities & Exposures) ids in your changelog entry.
| | > |
| | > | For further information see:
| | > |
| | > | [0] https://security-tracker.debian.org/tracker/CVE-2026-26824
| | > |     https://www.cve.org/CVERecord?id=CVE-2026-26824
| | > | [1] https://security-tracker.debian.org/tracker/CVE-2026-26825
| | > |     https://www.cve.org/CVERecord?id=CVE-2026-26825
| | > |
| | > | Please adjust the affected versions in the BTS as needed.
| | >
| | > --
| | > Dirk Eddelbuettel | edd@debian.org | http://dirk.eddelbuettel.com
| | >
| | > Support my Tour de Shore 2026 ride benefiting Maywood Fine Arts! More info at
| | > https://dirk.eddelbuettel.com/blog/2026/04/03#sponsor_tour_de_shore_2026
|
| --
| Dirk Eddelbuettel | edd@debian.org | http://dirk.eddelbuettel.com
|
| Support my Tour de Shore 2026 ride benefiting Maywood Fine Arts! More info at
| https://dirk.eddelbuettel.com/blog/2026/04/03#sponsor_tour_de_shore_2026