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CVE.org (no NVD analysis yet)· CNA freebsd

CVE-2026-58098: Heap out-of-bounds access in semop(2)

Noroxi assessment

Priority: Monitor (action score 33/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.11% (FIRST EPSS).
  • Someone with local access to the system can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: FreeBSD FreeBSD p1, p10, p14.

Low priority for now. Upgrade to FreeBSD FreeBSD p1, p10, p14 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

When semop(2) blocks waiting for a semaphore condition, it releases the per-set lock and sleeps. Upon waking, it checks the sequence number embedded in the semaphore set's IPC identifier to detect whether the set was removed while the caller was asleep. This sequence number is only 15 bits wide. If enough semaphore sets are created and destroyed in the same table slot while a caller is blocked, the counter wraps around, and semop(2) may falsely conclude that the original set still exists. The subsequent access to a semaphore within the set may then be out of bounds. An unprivileged local user can trigger an out-of-bounds access on kernel heap memory, potentially leading to privilege escalation.

HighCVSS 8.4 · v3.1—No exploit Fix available
Published
Oct 15, 2026
Updated
Oct 19, 2026
EPSS
0.1% · 1th percentile

Report tools

JSON

Action score

33

Monitor

Low priority for now.

CVSS
33 / 40 · 8.4 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-58098

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
freebsdfreebsd

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • freebsd freebsd14.4
  • freebsd freebsd14.5
  • freebsd freebsd15.0
  • freebsd freebsd15.1

Versions reported by the vendor

Affected version ranges reported by the assigning authority (freebsd). Independent of NVD's CPE analysis and usually ahead of it.

  • FreeBSD FreeBSD

    • 15.1-RELEASE and later · before p4affected · release
    • 15.0-RELEASE and later · before p14affected · release
    • 14.5-RELEASE and later · before p1affected · release
    • 14.4-RELEASE and later · before p10affected · release

Same product

freebsd: all records

Other highest-scoring records for the same primary product.

  • CVE-2020-7457In FreeBSD 12.1-STABLE before r359565, 12.1-RELEASE before p7, 11.4-STABLE before r362975, 11.4-RELEASE before p1, and 11.3-RELEASE before p
    60This week
  • CVE-2006-0900nfsd in FreeBSD 6.0 kernel allows remote attackers to cause a denial of service via a crafted NFS mount request, as demonstrated by the Prot
    51Plan
  • CVE-2018-17157In FreeBSD before 11.2-STABLE(r340854) and 11.2-RELEASE-p5, an integer overflow error when handling opcodes can cause memory corruption by s
    46Plan

Published before and after this one in the same product

  • ← EarlierCVE-2026-101307Oct 15, 2026 · Remotely triggerable buffer overflow in tcp_rack
    32Monitor
  • ← EarlierCVE-2026-101308Oct 15, 2026 · TOCTOU race between sound(4) buffer resizing and mmap
    22Monitor
  • Later →CVE-2026-58099Oct 15, 2026 · Memory safety bugs in kqueue copy-on-fork implementation
    28Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
FreeBSD FreeBSDp1Vendor (CNA)
FreeBSD FreeBSDp10Vendor (CNA)
FreeBSD FreeBSDp14Vendor (CNA)
FreeBSD FreeBSDp4Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. Fix recordedsame day
  3. TodayNov 10, 2026+26 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

  • CVE-2026-45253147 days apartMissing validation in ptrace(PT_SC_REMOTE)
    33Monitor
  • CVE-2026-3038220 days apartLocal DoS and possible privilege escalation via routing sockets
    30Monitor

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-787 · Out-of-bounds Write

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. CVSS— → 8.4
  2. Severity— → high
  3. SSVC exploitation— → none
  4. Exploit maturity— → none
  5. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records