4.8
MEDIUM CVSS 4.0
CVE-2026-2703
xlnt-community xlnt Encrypted XLSX File base64.cpp decode_base64 off-by-one
Description

A weakness has been identified in xlnt-community xlnt up to 1.6.1. Impacted is the function xlnt::detail::decode_base64 of the file source/detail/cryptography/base64.cpp of the component Encrypted XLSX File Parser. Executing a manipulation can lead to off-by-one. The attack requires local access. The exploit has been made available to the public and could be used for attacks. This patch is called f2d7bf494e5c52706843cf7eb9892821bffb0734. Applying a patch is advised to resolve this issue.

INFO

Published Date :

Feb. 19, 2026, 7:17 a.m.

Last Modified :

Feb. 19, 2026, 3:52 p.m.

Remotely Exploit :

No
Affected Products

The following products are affected by CVE-2026-2703 vulnerability. Even if cvefeed.io is aware of the exact versions of the products that are affected, the information is not represented in the table below.

No affected product recoded yet

CVSS Scores
The Common Vulnerability Scoring System is a standardized framework for assessing the severity of vulnerabilities in software and systems. We collect and displays CVSS scores from various sources for each CVE.
Score Version Severity Vector Exploitability Score Impact Score Source
CVSS 2.0 LOW [email protected]
CVSS 3.1 LOW [email protected]
CVSS 4.0 MEDIUM [email protected]
Solution
Apply the provided patch to fix the off-by-one vulnerability in the Base64 decoding function.
  • Apply patch f2d7bf494e5c52706843cf7eb9892821bffb0734.
  • Update the xlnt-community library to a patched version.
CWE - Common Weakness Enumeration

While CVE identifies specific instances of vulnerabilities, CWE categorizes the common flaws or weaknesses that can lead to vulnerabilities. CVE-2026-2703 is associated with the following CWEs:

Common Attack Pattern Enumeration and Classification (CAPEC)

Common Attack Pattern Enumeration and Classification (CAPEC) stores attack patterns, which are descriptions of the common attributes and approaches employed by adversaries to exploit the CVE-2026-2703 weaknesses.

We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).

Results are limited to the first 15 repositories due to potential performance issues.

The following list is the news that have been mention CVE-2026-2703 vulnerability anywhere in the article.

The following table lists the changes that have been made to the CVE-2026-2703 vulnerability over time.

Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.

  • New CVE Received by [email protected]

    Feb. 19, 2026

    Action Type Old Value New Value
    Added Description A weakness has been identified in xlnt-community xlnt up to 1.6.1. Impacted is the function xlnt::detail::decode_base64 of the file source/detail/cryptography/base64.cpp of the component Encrypted XLSX File Parser. Executing a manipulation can lead to off-by-one. The attack requires local access. The exploit has been made available to the public and could be used for attacks. This patch is called f2d7bf494e5c52706843cf7eb9892821bffb0734. Applying a patch is advised to resolve this issue.
    Added CVSS V4.0 AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
    Added CVSS V3.1 AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
    Added CVSS V2 (AV:L/AC:L/Au:S/C:N/I:N/A:P)
    Added CWE CWE-189
    Added CWE CWE-193
    Added Reference https://github.com/oneafter/0128/blob/main/xl1/repro
    Added Reference https://github.com/xlnt-community/xlnt/
    Added Reference https://github.com/xlnt-community/xlnt/commit/f2d7bf494e5c52706843cf7eb9892821bffb0734
    Added Reference https://github.com/xlnt-community/xlnt/issues/137
    Added Reference https://vuldb.com/?ctiid.346649
    Added Reference https://vuldb.com/?id.346649
    Added Reference https://vuldb.com/?submit.754377
EPSS is a daily estimate of the probability of exploitation activity being observed over the next 30 days. Following chart shows the EPSS score history of the vulnerability.
Vulnerability Scoring Details
Base CVSS Score: 4.8
Attack Vector
Attack Complexity
Attack Requirements
Privileges Required
User Interaction
VS Confidentiality
VS Integrity
VS Availability
SS Confidentiality
SS Integrity
SS Availability
Base CVSS Score: 3.3
Attack Vector
Attack Complexity
Privileges Required
User Interaction
Scope
Confidentiality Impact
Integrity Impact
Availability Impact
Base CVSS Score: 1.7
Access Vector
Access Complexity
Authentication
Confidentiality Impact
Integrity Impact
Availability Impact