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CVE-2021-1815· NVD / CVE Program· CNA apple

A parsing issue in the handling of directory paths was addressed with improved path validation.

A parsing issue in the handling of directory paths was addressed with improved path validation. This issue is fixed in macOS Big Sur 11.3, iOS 14.5 and iPadOS 14.5, watchOS 7.4, tvOS 14.5. A local user may be able to modify protected parts of the file system.

MediumCVSS 5.5 · v3.1—No exploit No fix recorded
Published
Sep 8, 2021
Updated
Jun 16, 2026
EPSS
0.4% · 32th percentile
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Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.4%

Affected systems

VendorProduct
appleipados
appleiphone os
applemacos
appletvos
applewatchos

Affected versions

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

  • apple ipadosbefore 14.5
  • apple iphone osbefore 14.5
  • apple macos11.0 and later · before 11.3
  • apple tvosbefore 14.5
  • apple watchosbefore 7.4

Versions reported by the vendor

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

  • Apple iOS and iPadOS

    • unspecified and later · before 14.5affected

  • Apple macOS

    • unspecified and later · before 11.3affected

  • Apple tvOS

    • unspecified and later · before 14.5affected

  • Apple watchOS

    • unspecified and later · before 7.4affected

Same product

apple: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-30860An integer overflow was addressed with improved input validation.KEV
    84Now
  • CVE-2025-43300An out-of-bounds write issue was addressed with improved bounds checking.KEV
    80Now
  • CVE-2023-41064A buffer overflow issue was addressed with improved memory handling.KEV
    77This week
  • CVE-2023-32434An integer overflow was addressed with improved input validation.KEV
    76This week
  • CVE-2025-24085A use after free issue was addressed with improved memory management.KEV
    75This week
  • CVE-2023-41993The issue was addressed with improved checks.KEV
    72This week

Remediation

Which version to upgrade to

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

No fix version is recorded for this entry. Check the references for vendor advisories.

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.

No dated events beyond publication.

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.

No credits in the CNA record.

Variant candidates

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

—

Chain candidates

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

  • CVE-2021-3086715 days apartThe issue was addressed with improved authentication.
    22Monitor
  • CVE-2021-306670 days apartA logic issue was addressed with improved validation.
    21Monitor

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.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-22 · Improper Limitation of a Pathname to a Restricted Directory ('Path Traversal')

CVSS vector

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

nvd-primary

Root cause

A user-supplied file name is joined with the allowed directory, but the result is never checked to confirm it is still inside that directory.

The bug in code

The whole CWE-22 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

ts
const file = path.join(ROOT, req.query.name);res.sendFile(file);

Fixed

ts
const file = path.resolve(ROOT, req.query.name);if (!file.startsWith(ROOT + path.sep)) {  return res.sendStatus(400);}res.sendFile(file);

Attack context

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

ATT&CK techniques

—

Noroxi analysis

No Noroxi analysis for this record yet

We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.

We use this product, ask for help

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

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

All records