CVE-2026-35453: PhpSpreadsheet is a library for reading and writing spreadsheet files

Routine

MEDIUM 5.4UPGRADE

CVE-2026-35453 is a medium-severity flaw (CVSS 5.4) affecting phpspreadsheet. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

PhpSpreadsheet is a library for reading and writing spreadsheet files. In versions 1.30.3 and earlier, 2.0.0 through 2.1.15, 2.2.0 through 2.4.4, 3.3.0 through 3.10.4, and 4.0.0 through 5.6.0, the HTML Writer skips htmlspecialchars() output escaping when a cell uses a custom number format containing the @ text placeholder with additional literal text (e.g., @ "items"). The escaping is only applied when the formatted output strictly equals the ori

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	5.4 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	Low
User interaction	Required
EPSS exploit chance	0.2% (top 90%)
CISA exploited list	No
Weakness	CWE-79
Published	2026-05-05
Last modified	2026-07-24

Publisher (CNA): GitHub, Inc. · Vendor: phpoffice

Last updated 2026-07-24 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-05 20:16 UTCPublished CVE record published
2026-07-24 21:10 UTCUpdated Record last modified

phpoffice phpspreadsheet UPGRADE

Affected: < 1.30.4 · >= 2.0.0 and < 2.1.16 · >= 2.2.0 and < 2.4.5 · >= 3.3.0 and < 3.10.5 · >= 4.0.0 and < 5.7.0

Fixed in: 1.30.4, 2.1.16, 2.4.5, 3.10.5, 5.7.0

Safe to downgrade to: a release before 2.0.0

1. Check installed version

apt-cache policy phpspreadsheet || rpm -q phpspreadsheet || phpspreadsheet --version

2. UPGRADE to 1.30.4 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade phpspreadsheet

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade phpspreadsheet

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 2.0.0 (Debian / Ubuntu)

apt-cache madison phpspreadsheet sudo apt install phpspreadsheet=<VERSION_BEFORE_2.0.0> sudo apt-mark hold phpspreadsheet

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list phpspreadsheet sudo dnf downgrade phpspreadsheet-<VERSION_BEFORE_2.0.0> sudo dnf versionlock add phpspreadsheet

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-35453?

phpspreadsheet: upgrade to 1.30.4, 2.1.16, 2.4.5, 3.10.5, 5.7.0. Exact commands for each OS are on this page.

Is CVE-2026-35453 being exploited?

CVE-2026-35453 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-35453 affect?

CVE-2026-35453 affects phpspreadsheet. Severity is medium (CVSS 5.4). PhpSpreadsheet is a library for reading and writing spreadsheet files. In versions 1.30.3 and earlier, 2.0.0 through 2.1.15, 2.2.0 through 2.4.4, 3.3.0 through 3.10.4, and 4.0.0 through 5.6.0, the HTML Writer skips htmlspecialchars() output

How urgent is CVE-2026-35453?

Priority 26/100. Public exploit reference

Related CVEs

CVE-2026-40296 MEDIUM 5.4 UPGRADE PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files
CVE-2026-40863 HIGH 7.5 UPGRADE PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files
CVE-2026-40902 HIGH 7.5 UPGRADE PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files
CVE-2026-34084 CRITICAL 9.8 UPGRADE PhpSpreadsheet is a library for reading and writing spreadsheet files

References

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