Libstdc++: overflow leaves streambuf in inconsistent state on i/o error.
- Exploited
- No known exploitation
- Fix
- No fix listed
- Who is exposed
- Not reported
- Last modified
- Whether it needs action now or is a reference record, by fixed rules, with why. Last checked is when cve.now last re-read it.What do these mean? →
- Reference
- Last checked
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 26/100 · provisional
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
Libstdc++, the C++ standard library, is affected: a failed byte-by-byte write during file stream processing can leave its internal buffer inconsistent, letting an attacker cause a buffer overflow that may lead to denial of service or memory corruption. An attacker can reach this remotely, without logging in, but it requires a user to take some action and repeated write failures in the affected service.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
Read the original description
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.
cve.now Index
- Exploitation0/40No signal
- Exposure7/25Reachable over the network without a login · Unknown: No advisory context yet
- Reach10/20Shipped in major Linux distributions
- Severity4.2/10CVSS 4.2
- No patch5/5No patch listed yet
What would change the score
- Would score about 81 if added to CISA KEV
- Would score about 76 if CISA's SSVC rates exploitation active
- Would score about 41 if advisories confirm default setups are exposed
Check your systems with an agent
Paste this into a coding or ops agent. It checks your systems read-only and reports a table per asset.
Check whether my systems are affected by CVE-2026-125709 (Libstdc++: overflow leaves streambuf in inconsistent state on i/o error.), using the cve.now data below. Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only. What cve.now has for CVE-2026-125709 (entry last updated 2026-11-10): Affected: - Red Hat Red Hat Enterprise Linux 10: version range not reported - Red Hat Red Hat Enterprise Linux 10: version range not reported - Red Hat Red Hat Enterprise Linux 10: version range not reported - Red Hat Red Hat Enterprise Linux 10: version range not reported - Red Hat Red Hat Enterprise Linux 6: version range not reported - Red Hat Red Hat Enterprise Linux 6: version range not reported - Red Hat Red Hat Enterprise Linux 6: version range not reported - Red Hat Red Hat Enterprise Linux 6: version range not reported - Red Hat Red Hat Enterprise Linux 6: version range not reported - Red Hat Red Hat Enterprise Linux 7: version range not reported - and 15 more affected products, listed on https://cve.now/CVE-2026-125709 Fixed versions: none listed yet. Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory. CISA KEV: CVE-2026-125709 is not listed as of cve.now's last read. This KEV status is for CVE-2026-125709 only. If you also check another CVE, look up its own KEV status; never assume it from this one. How to check: - Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory. Verify against the linked advisories before concluding, and cite the date you read each one: - https://bugzilla.redhat.com/show_bug.cgi?id=2569390 - https://access.redhat.com/security/cve/CVE-2026-125709 Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing. Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action. Entry: https://cve.now/CVE-2026-125709 For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-125709.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- gcc
Version range not reported
- gcc-toolset-15-gcc
Version range not reported
- gcc-toolset-16-gcc
Version range not reported
- mingw-gcc
Version range not reported
- compat-gcc-295
Version range not reported
- compat-gcc-296
Version range not reported
- compat-gcc-32
Version range not reported
- compat-gcc-34
Version range not reported
Show all 25 packagesShow fewer packages
- gcc
Version range not reported
- compat-gcc-32
Version range not reported
- compat-gcc-34
Version range not reported
- compat-gcc-44
Version range not reported
- gcc
Version range not reported
- gcc
Version range not reported
- gcc-toolset-15-gcc
Version range not reported
- mingw-gcc
Version range not reported
- gcc
Version range not reported
- gcc-toolset-15-gcc
Version range not reported
- gcc-toolset-16-gcc
Version range not reported
- mingw-gcc
Version range not reported
- gcc
Version range not reported
- gcc13
Version range not reported
- openshift/ose-rhel-coreos-8
Version range not reported
- openshift/ose-rhel-coreos-9
Version range not reported
- openshift/ose-rhel-coreos-9
Version range not reported
Evidence 4
CVE record · 2
Establishes: The identifier and description.
- Record
- Record
Write-ups · 1
Establishes: Technical detail and context.
- Report
Other links · 1
- Link
Corrections
None so far.
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