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CVE-2021-1871· NVD / CVE Program· CNA apple

A logic issue was addressed with improved restrictions.

Noroxi assessment

Priority: This week (action score 71/100)

  • CISA has confirmed exploitation in the wild (Nov 3, 2021). Remediation deadline for US federal agencies: Nov 17, 2021.
  • Probability of exploitation in the next 30 days: 7% (FIRST EPSS); higher than 94% of all records.
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: accountsservice (AlmaLinux:8) 0.6.55-2.el8; accountsservice-devel (AlmaLinux:8) 0.6.55-2.el8; accountsservice-libs (AlmaLinux:8) 0.6.55-2.el8.
  • Mentioned 3 times in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Don’t wait for the next maintenance window. Upgrade to accountsservice (AlmaLinux:8) 0.6.55-2.el8; accountsservice-devel (AlmaLinux:8) 0.6.55-2.el8; accountsservice-libs (AlmaLinux:8) 0.6.55-2.el8 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 · CISA KEV · FIRST EPSS

A logic issue was addressed with improved restrictions. This issue is fixed in macOS Big Sur 11.2, Security Update 2021-001 Catalina, Security Update 2021-001 Mojave, iOS 14.4 and iPadOS 14.4. A remote attacker may be able to cause arbitrary code execution. Apple is aware of a report that this issue may have been actively exploited..

CriticalCVSS 9.8 · v3.1KEVWeaponized Fix available
Published
Apr 2, 2021
Updated
Jun 16, 2026
EPSS
7.0% · 94th percentile
CWE
—

Report tools

JSON

Action score

71

This week

Don’t wait for the next maintenance window.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
30 / 30 · Listed
EPSS
2 / 30 · 7.0%

CISA SSVC decision

Exploitation
active
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

Actively exploited in the wild

CISA added this to its Known Exploited Vulnerabilities catalog on Nov 3, 2021. That signals real attacks, not theory.

Remediation deadline for US federal agencies: Nov 17, 2021.

Get told when this record changes

  • In CISA KEV: exploitation in the wild confirmed
  • Weaponized exploit exists
  • A fix has been released

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

Follow CVE-2021-1871

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
appleipados
appleiphone os
applemac os x
applemacos
debiandebian linux
fedoraprojectfedora

Affected versions

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

  • apple ipadosbefore 14.4
  • apple iphone osbefore 14.4
  • apple mac os x10.15 and later · before 10.15.7
  • apple mac os x10.15.7
  • apple macos11.0.1 and later · before 11.2
  • debian debian linux10.0
  • fedoraproject fedora33

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 14.4affected

  • Apple macOS

    • unspecified and later · before 11.2affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
AlmaLinux:8accountsservicebefore 0.6.55-2.el80.6.55-2.el8
AlmaLinux:8accountsservice-develbefore 0.6.55-2.el80.6.55-2.el8
AlmaLinux:8accountsservice-libsbefore 0.6.55-2.el80.6.55-2.el8
AlmaLinux:8gdmbefore 1:40.0-15.el81:40.0-15.el8
AlmaLinux:8gnome-autoarbefore 0.2.3-2.el80.2.3-2.el8
AlmaLinux:8gnome-calculatorbefore 3.28.2-2.el83.28.2-2.el8
AlmaLinux:8gnome-classic-sessionbefore 3.32.1-20.el83.32.1-20.el8
AlmaLinux:8gnome-control-centerbefore 3.28.2-28.el83.28.2-28.el8
AlmaLinux:8gnome-control-center-filesystembefore 3.28.2-28.el83.28.2-28.el8
AlmaLinux:8gnome-online-accountsbefore 3.28.2-3.el83.28.2-3.el8
AlmaLinux:8gnome-online-accounts-develbefore 3.28.2-3.el83.28.2-3.el8
AlmaLinux:8gnome-sessionbefore 3.28.1-13.el83.28.1-13.el8
AlmaLinux:8gnome-session-kiosk-sessionbefore 3.28.1-13.el83.28.1-13.el8
AlmaLinux:8gnome-session-wayland-sessionbefore 3.28.1-13.el83.28.1-13.el8
AlmaLinux:8gnome-session-xsessionbefore 3.28.1-13.el83.28.1-13.el8
AlmaLinux:8gnome-settings-daemonbefore 3.32.0-16.el8.alma3.32.0-16.el8.alma
AlmaLinux:8gnome-shellbefore 3.32.2-40.el83.32.2-40.el8
AlmaLinux:8gnome-shell-extension-apps-menubefore 3.32.1-20.el83.32.1-20.el8
AlmaLinux:8gnome-shell-extension-auto-move-windowsbefore 3.32.1-20.el83.32.1-20.el8
AlmaLinux:8gnome-shell-extension-commonbefore 3.32.1-20.el83.32.1-20.el8
AlmaLinux:8gnome-shell-extension-dash-to-dockbefore 3.32.1-20.el83.32.1-20.el8
AlmaLinux:8gnome-shell-extension-desktop-iconsbefore 3.32.1-20.el83.32.1-20.el8
AlmaLinux:8gnome-shell-extension-disable-screenshieldbefore 3.32.1-20.el83.32.1-20.el8
AlmaLinux:8gnome-shell-extension-drive-menubefore 3.32.1-20.el83.32.1-20.el8

+75

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.

Product / packageFixed versionSource
almalinux:accountsservice0.6.55-2.el8 · AlmaLinux:8Package registry (OSV)
almalinux:accountsservice-devel0.6.55-2.el8 · AlmaLinux:8Package registry (OSV)
almalinux:accountsservice-libs0.6.55-2.el8 · AlmaLinux:8Package registry (OSV)
almalinux:gdm1:40.0-15.el8 · AlmaLinux:8Package registry (OSV)
almalinux:gnome-autoar0.2.3-2.el8 · AlmaLinux:8Package registry (OSV)
almalinux:gnome-calculator3.28.2-2.el8 · AlmaLinux:8Package registry (OSV)
almalinux:gnome-classic-session3.32.1-20.el8 · AlmaLinux:8Package registry (OSV)
almalinux:gnome-control-center3.28.2-28.el8 · AlmaLinux:8Package registry (OSV)
almalinux:gnome-control-center-filesystem3.28.2-28.el8 · AlmaLinux:8Package registry (OSV)
almalinux:gnome-online-accounts3.28.2-3.el8 · AlmaLinux:8Package registry (OSV)
almalinux:LibRaw0.19.5-3.el8 · AlmaLinux:8Package registry (OSV)
almalinux:LibRaw-devel0.19.5-3.el8 · AlmaLinux:8Package registry (OSV)
debian:webkit2gtk2.32.0-2 · Debian:12Package registry (OSV)
debian:wpewebkit2.32.0-2 · Debian:12Package registry (OSV)
opensuse:webkit2gtk32.32.0-lp152.2.13.1 · openSUSE:Leap 15.2Package registry (OSV)
red hat:LibRaw0:0.19.5-3.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:LibRaw-debuginfo0:0.19.5-3.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:LibRaw-debugsource0:0.19.5-3.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:webkit2gtk30:2.32.3-2.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:webkit2gtk3-debuginfo0:2.32.3-2.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:webkit2gtk3-debugsource0:2.32.3-2.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:webkit2gtk3-devel0:2.32.3-2.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:webkit2gtk3-devel-debuginfo0:2.32.3-2.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:webkit2gtk3-jsc0:2.32.3-2.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:webkit2gtk3-jsc-debuginfo0:2.32.3-2.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:webkit2gtk3-jsc-devel0:2.32.3-2.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
red hat:webkit2gtk3-jsc-devel-debuginfo0:2.32.3-2.el8 · Red Hat:enterprise_linux:8::appstreamPackage registry (OSV)
rocky linux:accountsservice0:0.6.55-2.el8 · Rocky Linux:8Package registry (OSV)
rocky linux:gdm1:40.0-15.el8 · Rocky Linux:8Package registry (OSV)
rocky linux:gnome-autoar0:0.2.3-2.el8 · Rocky Linux:8Package registry (OSV)

+10

Exploit status

Weaponized

A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.

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. CISA KEV+214 d
  3. TodayOct 16, 2026+2023 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.

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.

No nightly-computed relations.

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).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Anyone who can reach it over the internet 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
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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

nvd-primary

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. Fix✗ → ✓

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

References

Show all references (4 more)

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

All records