---
id: "CVE-2026-125709"
page: "https://infrastack.ai/live/CVE-2026-125709"
kind: "vulnerability"
aliases: ["CVE-2026-125709"]
title: "libstdc++: failed file writes can overflow a buffer, causing crash or memory corruption"
severity: "medium"
cvss: 4.2
epss: null
exploited: false
status: "open"
category: "runtime"
products: []
ecosystems: []
tags: ["c++", "gcc", "libstdc++", "runtime"]
not_affected_if: ["no-file-stream-writes"]
published_at: "2026-11-10T12:17:18+00:00"
first_seen_at: "2026-11-10T12:21:54+00:00"
updated_at: "2026-11-10T12:22:48+00:00"
sources: [{"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-125709", "first_seen_at": "2026-11-10T12:21:54+00:00"}]
exploit_sources: []
---

# libstdc++: failed file writes can overflow a buffer, causing crash or memory corruption

Link for people: https://infrastack.ai/live/CVE-2026-125709 (this .md is for agents)

When a byte-by-byte write to a file stream fails, libstdc++ may still append the data to its internal buffer. An attacker who can force repeated write failures in an affected service can trigger a buffer overflow, leading to denial of service or memory corruption.

_Summary, check and fix written by a model from the sources; labelled as such._

## Timeline

- 2026-11-10T12:21:54+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-125709

## From the sources

A flaw was found in libstdc++. When a byte-by-byte write operation fails during file stream processing, the library may still append data into the internal memory buffer. An attacker capable of inducing repeated write failures in an affected service can trigger a buffer overflow, potentially resulting in a Denial of Service (DoS) or memory corruption.

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