Evidence used
- No CISA KEV confirmation is currently recorded.
- Exploitation requires an existing local or physical foothold with privileges.
- EPSS is 0.14% for the current model date.
BlackTreeCVE IntelligenceFull vulnerability report · 2026
CVE-2026-17042High confidence
Power System Out-of-bounds Read
IBM · Power Systems Firmware
7.3HighCVSS 3.1
Within 7 days
Patch availableHigh technical severity; prioritise exposed affected systems while verifying vendor guidance.
R
Open reassessment dashboard →Operational reassessment
Published severity in operational context
Published severityHigh→Operational priority:Medium, lowered one band.downgradedsince 19 Aug 2026
Compensating controls
- Validate the affected product branch and deploy the verified fixed release.
- Restrict local access and enforce least privilege on affected hosts.
- Monitor vendor guidance and exploitation sources for a material change.
Verification
- Confirm that the asset runs IBM Power Systems Firmware and falls inside the recorded affected range.
- Verify the installed build against the product-specific fixed version after deployment.
- Validate exposure, authentication requirements and compensating controls in the actual environment.
- Reopen this reassessment when CVSS, KEV, EPSS, exploit evidence or remediation changes.
High technical severity; prioritise exposed affected systems while verifying vendor guidance.
Patch available01
What, why and how
IBM Power Systems Firmware FW950.00 through FW950.H2, OP940.00 through OP940.a1 (Power9), and OP940.00 - OP940.81 (Power HMC) is affected by a vulnerability in host firmware NVRAM parsing. An attacker with root access to a guest partition on an OpenPOWER system can write a specially crafted NVRAM image, causing the host firmware boot stage to crash with possible memory corruption. This condition persists until operator intervention — clearing NVRAM via the service processor — to restore normal operation. This vulnerability only affects OpenPOWER systems; systems running PowerVM are not affected. Successful exploitation results in an integrity and availability impact to the managed system.
What
IBM Power Systems Firmware FW950.00 through FW950.H2, OP940.00 through OP940.a1 (Power9), and OP940.00 - OP940.81 (Power HMC) is affected by a vulnerability in host firmware NVRAM parsing. An attacker with root access to a guest partition on an OpenPOWER system can write a specially crafted NVRAM image, causing the host firmware boot stage to crash with possible memory corruption. This condition persists until operator intervention — clearing NVRAM via the service processor — to restore normal operation. This vulnerability only affects OpenPOWER systems; systems running PowerVM are not affected. Successful exploitation results in an integrity and availability impact to the managed system.
Why
The product reads data past the end, or before the beginning, of the intended buffer.
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.
What
IBM Power Systems Firmware FW950.00 through FW950.H2, OP940.00 through OP940.a1 (Power9), and OP940.00 - OP940.81 (Power HMC) is affected by a vulnerability in host firmware NVRAM parsing. An attacker with root access to a guest partition on an OpenPOWER system can write a specially crafted NVRAM image, causing the host firmware boot stage to crash with possible memory corruption. This condition persists until operator intervention — clearing NVRAM via the service processor — to restore normal operation. This vulnerability only affects OpenPOWER systems; systems running PowerVM are not affected. Successful exploitation results in an integrity and availability impact to the managed system.
Why
The product reads data past the end, or before the beginning, of the intended buffer.
How
An attacker operating through local access may attempt exploitation with low privileges. If successful, the issue may disrupt the affected service.
02
Exploit reality and attack path
CVSS severity, EPSS forecast probability, public exploit material and CISA-confirmed exploitation are separate signals.
Observed exploitation No confirmed evidence
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No CISA KEV match was present at the last successful refresh. This means no confirmation from that source, not proof of no exploitation.
Public PoC / exploit material None recorded
?
Confirmed exploitation and public exploit material are separate signals. Attacks can occur without public proof-of-concept or exploit code.No exploit-tagged reference or CISA SSVC proof-of-concept state is currently recorded. Research may still exist outside the structured feeds.
- Likely attack path
- local access → Out-of-bounds Read → disrupt the affected service
- Attack surface
- Local
- Privileges required
- Low: a basic authenticated account is required
- User interaction
- None
- Attack complexity
- Low: no specialised conditions are recorded
- Security boundary
- Changed: exploitation can affect a different security authority
- Weakness
?
CWE means Common Weakness Enumeration: a standard category for the underlying weakness. - CWE-125 ↗
CWE-125: Out-of-bounds Read. The product reads data past the end, or before the beginning, of the intended buffer.
- CVSS vector
?
CVSS means Common Vulnerability Scoring System. The vector records the metric values used to calculate technical severity. CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:N/I:L/A:HCommon Vulnerability Scoring System 3.1: the compact vector below is decoded into plain language.
AVLocalAttack vector: The attacker needs local access to the vulnerable system.ACLowAttack complexity: No specialised conditions are required beyond attacker-controlled input.PRLowPrivileges required: The attacker needs basic user-level privileges.UINoneUser interaction: No action by another user is required.SChangedScope: The attack can affect a component governed by a different security authority.CNoneConfidentiality impact: No direct loss is represented by this metric.ILowIntegrity impact: A successful attack can cause a limited loss.AHighAvailability impact: A successful attack can cause a major loss.- Post-exploitation / living off the land
- The issue can support a local privilege or sandbox boundary transition; normal system utilities may then be available in the gained context.
03
Patch and workaround
Operational remediation based on structured source evidence.
- Status
?
Patch availability is based on structured fixed-version fields and authoritative update references. If no fix is verified, check the vendor advisory before making a change. - Patch available
- Fixed
- Customers with the products below should install FW950.H3(950_230) or newer to remediate this vulnerability.
- Power 9
- * IBM Power System S922 (9009-22G)
- * IBM Power System H922 (9223-22S)
- * IBM Power System S914 (9009-41G)
- * IBM Power System S924 (9009-42G)
- * IBM Power System H924 (9223-42S)
- * IBM Power System E950 (9040-MR9)
- * IBM Power System E980 (9080-M9S)
- Customers with the products below should install OP940.a2 or newer to remediate this vulnerability.
- * IBM Power System AC922 (8335-GTH, 8335-GTX)
- Customers with the products below should install OP940.82 or newer to remediate this vulnerability.
- Action
- Review the linked authoritative reference and apply the recorded fixed release appropriate to the affected product branch.
- Workaround
- No verified workaround is recorded. Limit untrusted access and use least privilege until authoritative guidance is available.
Official vendor articles1 stored document
Linked articles are downloaded and versioned as source evidence. A CVE mention or approved update relationship does not, by itself, verify a fix for every product branch.
- Security Bulletin: This Power System update is being released to address CVE-2026-17042 →Original publisher ↗Searchable text snapshot · Captured 27 Sep 2026IBM Support No results were found for your search query. Tips To return expected results, you can: Reduce the number of search terms. Each term you use focuses the search further. Check your spelling. A single misspelled or incorrectly typed term can change your result. Try substituting synonyms for your original ter
04
Evidence and provenance
Published 19 Aug 2026 · Last source change 19 Aug 2026, 19:46 UTC · CWE-125 · Out-of-bounds Read
CVE recordCVE.org · 5.2
CVSS sourceCNA
EPSS source FIRST · tracked since 2026-08-23
?
The date BlackTree first stored a score for this CVE from the daily FIRST EPSS feed.European sourceENISA EUVD · EUVD-2026-62696
Product sourceCNA
Remediation sourceCVE/CNA references
CWE sourceCNA
NVD statusNVD enriched
Core structured fields are present and their contributing authorities are shown above.
Material change intelligence
View recent updates ↗What changed after publication
- Vendor guidanceAuthoritative vendor guidance changed: added vendor advisory: ibm.com/7283240.psirt@us.ibm.com ↗
- Before
- no authoritative guidance recorded
- After
- vendor advisory: ibm.com/7283240
- Catalogue recordCVE added to the BlackTree catalogue.CNA ↗
Technical terms and abbreviations used in this report
- CVE
- Common Vulnerabilities and Exposures: the public identifier for one disclosed vulnerability.
- CVSS
- Common Vulnerability Scoring System: a technical severity framework; it is not patching priority by itself.
- EPSS
- Exploit Prediction Scoring System: FIRST's estimate of the probability that exploitation activity will be observed in the next 30 days; it is a forecast, not confirmation.
- CWE
- Common Weakness Enumeration: the standard category describing the underlying software or hardware weakness.
- CNA
- CVE Numbering Authority: an organisation authorised to assign and publish CVE records.
- CISA ADP
- Cybersecurity and Infrastructure Security Agency Authorized Data Publisher: structured enrichment added to a CVE record.
- NVD
- National Vulnerability Database: NIST's enrichment service for CVE records.
- CERT / CSIRT
- A computer security incident response team that publishes warnings or coordinates incident response.
- PoC
- Proof of concept: public material that demonstrates or helps reproduce exploitation.
- CSAF
- Common Security Advisory Framework: a machine-readable format for security advisories.
- LoTL
- Living off the land: abuse of legitimate tools or system functions during an attack.