CVE-2026-15961

Data disclosure or DoS via format string

Published Aug 19, 2026 · Updated Aug 20, 2026

Format string vulnerability in IBM PowerVM Hypervisor before FW1060.81, FW1110.31, and FW1120.01 allows local users to read data or interrupt service via local input. IBM attributes the flaw to externally controlled format strings but has not disclosed the affected hypervisor routine or the specific path that treats attacker-influenced data as a format string. Exploitation requires high local privileges and high attack complexity, which limits exposure to guests or operators that already hold strong access on affected systems, but successful use can disclose memory contents or crash hypervisor functionality.

CVSS severity5.2
Medium
EPSS probability0.10%
Next 30 days · Sep 17, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Format string vulnerability in IBM PowerVM Hypervisor before FW1060.81, FW1110.31, and FW1120.01 allows local users to read data or interrupt service via local input. IBM attributes the flaw to externally controlled format strings but has not disclosed the affected hypervisor routine or the specific path that treats attacker-influenced data as a format string. Exploitation requires high local privileges and high attack complexity, which limits exposure to guests or operators that already hold strong access on affected systems, but successful use can disclose memory contents or crash hypervisor functionality.

The record

CVE
CVE-2026-15961
Published
Aug 19, 2026
Updated
Aug 20, 2026
Vendor
OpenBMC Project
Product
PowerVM Hypervisor
Classifications
CWE-134
Attack vector
local
Privileges
admin

Timeline

How it unfolded

  1. Aug 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Aug 20, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=FW1060.00 <=FW1060.80
  2. Affected versionversion=FW1110.00 <=FW1110.30
  3. Affected versionversion=FW1120.00

What conditions does exploitation require?

Attack vectorlocal
Required privilegesadmin

What is affected?

OpenBMC Project · PowerVM Hypervisorversion=FW1060.00 <=FW1060.80; version=FW1110.00 <=FW1110.30; version=FW1120.00

Published CVSS scores

5.2IBMCVSS:3.1/AV:L/AC:H/PR:H/UI:N/S:U/C:L/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 11, 2026Sep 17, 2026
Latest reporting daySep 17, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesadmin
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-134Use of Externally-Controlled Format String

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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