CVE-2026-108358

HIGHPre-NVD 8.88.8
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

This high-severity CVE scores 8.8 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.5% (41st percentile of EPSS-scored CVEs). No GitHub Security Advisory CVSS is on record for this CVE.

Triggered by: Headline CVSS from a secondary CVSS source
Sources: EPSS, a secondary CVSS source

Also known asEUVD-2026-108265 (ENISA EUVD) · GHSA-3x94-m842-937c (GitHub Security Advisories)Source: ENISA EUVD

8.8EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.5%CVSS: 8.8Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. Prior to 1.30.7, 2.1.19, 2.4.8, 3.10.8, and 5.10.0, XmlScanner::scan in src/PhpSpreadsheet/Reader/Security/XmlScanner.php uses a DOCTYPE detection pattern that accounts for NUL-byte interleaving but not ISO-2022 escape sequences in XLSX XML parts. The escape sequences prevent the scanner from matching the declaration, and XML charset normalization then removes the escape bytes before parsing, exposing a valid DOCTYPE and entity definitions. Processing an attacker-controlled XLSX can therefore cause entity-expansion denial of service on supported PHP versions and can permit local file access or SSRF on PHP before 8.0 or when LIBXML_NOENT is enabled. This issue is fixed in versions 1.30.7, 2.1.19, 2.4.8, 3.10.8, and 5.10.0.

CVSS v3
8.8
EG Score
8.8HIGHmedium confidence
EG Risk
55
EG Risk 55/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity88% × 45%
Impact severity (EG Severity): CVSS 8.8 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.5% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
EPSS PROB
0.5%
EPSS %ILE
41st
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (8.8): severity, escalated by confirmed exploitation. This CVE's 8.8 is its impact severity (EG Severity), not escalated.

EG Severity
8.8 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.a secondary CVSS source · CVSS v3.0 or v3.1
EG Likelihood
0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-27). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track at low or medium mission impact; Attend at high (mission-essential systems).

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

October 22, 2026

Last Modified

October 23, 2026

Advisory Details (10)

Auto-updated Oct 22, 2026
🔬 Proof of concept available. Patch available. Sources: github, github_commit, github_release.
GitHub release Patch Available

3.10.8

Patch available: PHPOffice/PhpSpreadsheet 3.10.8

https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/3.10.8
GitHub release Patch Available

2.4.8

Patch available: PHPOffice/PhpSpreadsheet 2.4.8

https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/2.4.8
GitHub release Patch Available

2.1.19

Patch available: PHPOffice/PhpSpreadsheet 2.1.19

https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/2.1.19
GitHub release Patch Available

1.30.7

Patch available: PHPOffice/PhpSpreadsheet 1.30.7

https://github.com/PHPOffice/PhpSpreadsheet/releases/tag/1.30.7
GitHub commit Patch Available

commit da13f40e8760 (PHPOffice/PhpSpreadsheet)

Patch available: PHPOffice/PhpSpreadsheet 1.30.7 (contains commit da13f40e8760)

https://github.com/PHPOffice/PhpSpreadsheet/commit/da13f40e8760d599b0e8a296017d4b028b20e86c
GitHub commit Patch Available

commit 9a0b48622ebf (PHPOffice/PhpSpreadsheet)

Patch available: PHPOffice/PhpSpreadsheet 2.4.8 (contains commit 9a0b48622ebf)

https://github.com/PHPOffice/PhpSpreadsheet/commit/9a0b48622ebfe93fa48cb9bc09ce57303bb07af9
GitHub commit Patch Available

commit 980b5c294493 (PHPOffice/PhpSpreadsheet)

Patch available: PHPOffice/PhpSpreadsheet 3.10.8 (contains commit 980b5c294493)

https://github.com/PHPOffice/PhpSpreadsheet/commit/980b5c294493856f1a25754f1e8a1d2185b93738
GitHub commit Patch Available

commit 89f455c133e1 (PHPOffice/PhpSpreadsheet)

Patch available: PHPOffice/PhpSpreadsheet 5.10.0 (contains commit 89f455c133e1)

https://github.com/PHPOffice/PhpSpreadsheet/commit/89f455c133e1a7e2d4abfadc43ce29eb7450d781
GitHub commit Patch Available

commit 299993894dce (PHPOffice/PhpSpreadsheet)

Patch available: PHPOffice/PhpSpreadsheet 2.1.19 (contains commit 299993894dce)

https://github.com/PHPOffice/PhpSpreadsheet/commit/299993894dce37aa3b64aa23e9a3f4bb77ab0e66
GitHub advisoryMentions a patch (unverified)🟡 PoC Available

XmlScanner Bypass via ISO-2022 Escape Sequences Allows XXE and Denial of Service · Advisory · PHPOffice/PhpSpreadsheet · GitHub

https://github.com/PHPOffice/PhpSpreadsheet/security/advisories/GHSA-3x94-m842-937c

Vendor Advisories for CVE-2026-108358(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Affected Packages

(1 across 1 ecosystem)
Packagist(1)
PackageVulnerable rangeFix by version rangeDependents
phpoffice/phpspreadsheet4.0.0 ... 5.9.0 (18 versions)
  • 4.0.0 up to 5.10.0: fixed in 5.10.0
  • 3.3.0 up to 3.10.8: fixed in 3.10.8
  • 2.2.0 up to 2.4.8: fixed in 2.4.8
  • 2.0.0 up to 2.1.19: fixed in 2.1.19
  • every version up to 1.30.7: fixed in 1.30.7
—

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 12× in last 7d / 15× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

  1. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  2. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  3. 2026-10-27 20:38 UTCEG score recompute
  4. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  5. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  6. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
  7. 2026-10-25 14:54 UTCEG score recompute
  8. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  9. 2026-10-23 22:30 UTCEG score recompute
  10. 2026-10-23 21:25 UTCEG score recompute
  11. 2026-10-23 19:47 UTCEG score recompute
  12. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.4% · 31st percentile
  13. 2026-10-22 18:26 UTCEG score recompute
  14. 2026-10-22 17:36 UTCEG score recomputeFirst assessed: 8.8 HIGH
  15. 2026-10-22 17:35 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-108358?
CVE-2026-108358 is a high-severity vulnerability; its CVE record was published on October 22, 2026. PhpSpreadsheet is a pure PHP library for reading and writing spreadsheet files. Prior to 1.30.7, 2.1.19, 2.4.8, 3.10.8, and 5.10.0, XmlScanner::scan in src/PhpSpreadsheet/Reader/Security/XmlScanner.php uses a DOCTYPE detection pattern that accounts for NUL-byte interleaving but not ISO-2022 escape…
When was the CVE record for CVE-2026-108358 published?
The CVE record for CVE-2026-108358 was published on October 22, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 23, 2026; the record at its source may have been updated since.
Is CVE-2026-108358 actively exploited?
CVE-2026-108358 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.5% probability of exploitation in the next 30 days (41st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-108358?
CVE-2026-108358 has a CVSS base score of 8.8 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-108358?
A fix for CVE-2026-108358 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-108358 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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