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NVD / CVE Program· CNA GitHub_M

CVE-2026-27447: OpenPrinting CUPS: Authorization bypass via case-insensitive group-member lookup

Noroxi assessment

Priority: Monitor (action score 25/100)

  • 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: 0.29% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. A user must open a link or visit a page. No special conditions are required; it is repeatable.
  • Fixed version: azl3 cups 2.4.16-1 on Azure Linux 3.0 2.4.17-1; cbl2 cups 2.3.3op2-11 on CBL-Mariner 2.0 Release Notes.

Low priority for now. Upgrade to azl3 cups 2.4.16-1 on Azure Linux 3.0 2.4.17-1; cbl2 cups 2.3.3op2-11 on CBL-Mariner 2.0 Release Notes 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

OpenPrinting CUPS is an open source printing system for Linux and other Unix-like operating systems. In versions 2.4.16 and prior, CUPS daemon (cupsd) contains an authorization bypass vulnerability due to case-insensitive username comparison during authorization checks. The vulnerability allows an unprivileged user to gain unauthorized access to restricted operations by using a user with a username that differs only in case from an authorized user. At time of publication, there are no publicly available patches.

MediumCVSS 6.3 · v3.1—No exploit Fix available
Published
Apr 3, 2026
Updated
Jul 24, 2026
EPSS
0.2% · 22th percentile

Report tools

JSON

Action score

25

Monitor

Low priority for now.

CVSS
25 / 40 · 6.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
proof of concept
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
6.3
CNA · GitHub_M
4.8
1.5 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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-2026-27447

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
openprintingcups

Affected versions

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

  • openprinting cupsup to 2.4.16 inclusive

Versions reported by the vendor

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

  • OpenPrinting cups

    • <= 2.4.16affected

Package-level exposure

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

EcosystemPackageAffected rangeFix
Alpine:v3.20cupsbefore 2.4.18-r02.4.18-r0
Debian:12cupsfrom 0—
Debian:14cupsbefore 2.4.17-12.4.17-1
openSUSE:Tumbleweedcupsbefore 2.4.17-1.12.4.17-1.1
Red Hat:hummingbird:1cupsbefore 0:2.4.17-1.hum10:2.4.17-1.hum1
Red Hat:hummingbird:1cups-clientbefore 0:2.4.17-1.hum10:2.4.17-1.hum1
Red Hat:hummingbird:1cups-develbefore 0:2.4.17-1.hum10:2.4.17-1.hum1
Red Hat:hummingbird:1cups-filesystembefore 0:2.4.17-1.hum10:2.4.17-1.hum1
Red Hat:hummingbird:1cups-ipptoolbefore 0:2.4.17-1.hum10:2.4.17-1.hum1
Red Hat:hummingbird:1cups-libsbefore 0:2.4.17-1.hum10:2.4.17-1.hum1
Red Hat:hummingbird:1cups-lpdbefore 0:2.4.17-1.hum10:2.4.17-1.hum1
Red Hat:hummingbird:1cups-printerappbefore 0:2.4.17-1.hum10:2.4.17-1.hum1
SUSE:Linux Enterprise Micro 5.3cupsbefore 2.2.7-150000.3.93.12.2.7-150000.3.93.1
SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5cupsbefore 1.7.5-20.67.11.7.5-20.67.1

Same product

openprinting: all records

Other highest-scoring records for the same primary product.

  • CVE-2025-58060cups has Authentication bypass with AuthType Negotiate
    32Monitor
  • CVE-2023-4504OpenPrinting CUPS/libppd Postscript Parsing Heap Overflow
    28Monitor
  • CVE-2023-34241CUPS vulnerable to use-after-free in cupsdAcceptClient()
    28Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2025-58436Nov 29, 2025 · OpenPrinting CUPS slow client can halt cupsd, leading to a possible DoS attack
    22Monitor
  • ← EarlierCVE-2025-61915Nov 29, 2025 · OpenPrinting CUPS vulnerable to stack based out-of-bound write
    26Monitor
  • Later →CVE-2026-34978Apr 3, 2026 · OpenPrinting CUPS: Path traversal in RSS notify-recipient-uri enables file write outside CacheDir/rss (and clobbering of job.cache)
    26Monitor

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
azl3 cups 2.4.16-1 on Azure Linux 3.02.4.17-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
cbl2 cups 2.3.3op2-11 on CBL-Mariner 2.0Release NotesMicrosoft (MSRC)
alpine:cups2.4.18-r0 · Alpine:v3.20Package registry (OSV)
debian:cups2.4.17-1 · Debian:14Package registry (OSV)
opensuse:cups2.4.17-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:cups0:2.4.17-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:cups-client0:2.4.17-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:cups-devel0:2.4.17-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:cups-filesystem0:2.4.17-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:cups-ipptool0:2.4.17-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:cups-libs0:2.4.17-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:cups-lpd0:2.4.17-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:cups-printerapp0:2.4.17-1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
suse:cups1.7.5-20.67.1 · SUSE:Linux Enterprise Server LTSS Extended Security 12 SP5Package registry (OSV)

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.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

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

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).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • A user must open a link or visit a page.
  • No special conditions are required; it is repeatable.

If successful

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

Weakness class (CWE)

CWE-863 · Incorrect Authorization

CVSS vector

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

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

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

All records