CVE-2026-12259
In nltk version 3.9.4, the `nltk.downloader.Downloader._download_package()` function writes downloaded package bytes to disk and may extract
CVSS
6.5
Medium
EPSS
0.1%
p1
KEV
—
Exploit Today
0
0-100
Published: Aug 3, 2026 · Last modified: Oct 15, 2026 · CWE-494
0.1%EPSS · 30 days0.1%
2026-09-242026-10-21
In nltk version 3.9.4, the `nltk.downloader.Downloader._download_package()` function writes downloaded package bytes to disk and may extract them before enforcing SHA-256 or MD5 checksum validation. This allows an attacker to tamper with the package response body for `info.url` through a compromised mirror, malicious proxy, or other source-substitution condition, leading to the installation of attacker-controlled package bytes. The vulnerability can result in malicious corpus or model content being trusted by downstream users or applications.
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-113717—21.1%
——6virtualenv is a tool for creating isolated virtual python environments. Prior to 21.14.9, PipInvoke.get_pip_install_cmd() handles --seeder pip --download by calling get_wheel(download=False) and then allowing pip to consult the configured index, bypassing virtualenv's download_wheel() and verify_wheel_digest() path. When virtualenv's default-index PyPI digest comparison remains enabled, an index candidate matching the bundled package and version can therefore be selected without comparison to PyPI SHA-256 metadata. Explicit custom-index settings already opt out of that comparison and remain outside this verification-bypass claim; the demonstrated configuration used a non-PyPI index while leaving the index environment variables unset so the comparison policy remained active. This condition does not independently defeat TLS or establish control of the index response. This issue is fixed in version 21.14.9.2dCVE-2026-1050367.5 HIG13.7%
——4EnergizeLab AI Station firmware, EilikO Linux robot firmware v2.1_20260617182218_release, and the EnergizeLab Windows desktop app 3.1.2 download firmware updates over plain HTTP and do not verify their integrity or authenticity. An attacker able to intercept or modify the traffic can substitute a malicious update.6dCVE-2026-936497.5 HIG4.3%
——1In the Eclipse Adoptium website (adoptium.net), in every deployment built from commit 0b24ea1 (2025-06-18) up to the fix in commit cbb53cf (2026-09-24), the post-download page /[locale]/download takes a download URL from the "link" query parameter and automatically navigates to it with a meta http-equiv="refresh". The URL is checked against a list of trusted prefixes using String.startsWith() on the raw string, while the browser applies RFC 3986 dot-segment normalisation before navigating, so a value such as https://github.com/adoptium/temurin/../../attacker/malware/releases/download/v1/jdk.exe passes the check but resolves to an attacker-controlled repository. A victim who follows a crafted adoptium.net link is shown the genuine "Thank you for downloading Eclipse Temurin" page while their browser downloads a binary of the attacker's choosing6dCVE-2026-86063—6.2%
——2Claude Code is an agentic coding tool. Prior to 2.1.179, the Claude Code and Claude Desktop plugin installation flow runs git checkout for a marketplace-pinned commit without verifying that the resulting HEAD equals the pinned 40-character SHA. An attacker who controls a plugin repository on a Git host that permits SHA-shaped branch names can create a branch named after the reviewed commit, causing checkout to select the branch tip and install attacker-controlled plugin code. Exploitation requires a user to install the malicious plugin and pin it to the ostensibly safe hash. This issue is fixed in version 2.1.179.9dCVE-2026-1101027.5 HIG1.8%
——1Powerlevel10k through 1.20.0 contains an insecure download vulnerability in the gitstatus/install script that disables TLS certificate verification with curl -k and skips integrity checks when no SHA-256 utility exists. Network-positioned attackers can intercept the github.com mirror request and substitute a malicious archive, which runs as the gitstatusd daemon under the user's account on every prompt.8dCVE-2026-1081607.5 HIG3.6%
——1AstronRPA through 1.1.6 contains a download of code without integrity check vulnerability that allows network attackers to deliver malicious updates by abusing the desktop client's auto-update mechanism. Attackers positioned between the client and server can serve a malicious update manifest and NSIS installer, which electron-updater installs without signature verification, executing code as the desktop user.13d