Which products and versions are affected by CVE-2023-26258?

Affected: Udp (Arcserve). The full list is in the CVE brief.

Is CVE-2023-26258 being exploited in the wild?

It is exploited in the wild, listed in CIRCL KEV, Industry KEV feed since Aug 19, 2025.

Is CVE-2023-26258 in the CISA KEV catalog?

No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.

Is there a public exploit for CVE-2023-26258?

A public exploit is reported by tracking sources, but no code link is listed yet.

Is there a fix for CVE-2023-26258?

Fixed versions are available, including Udp <=9.0.6034, Udp 9.0.6034.

How urgently should CVE-2023-26258 be patched?

Brandefense priority: patch immediately, because it is listed as exploited in the wild.

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On CISA KEVCritical

CVE-2023-26258Udp Authorization Bypass

Q: What is CVE-2023-26258?

Arcserve UDP through 9.0.6034 allows authentication bypass.

Q: How urgently should CVE-2023-26258 be patched?

Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Arcserve UDP through 9.0.6034 allows authentication bypass.

Published Jul 3, 2023 · Updated Nov 25, 2024

Key Facts

Patch immediately

CVE-2023-26258 is a critical-severity vulnerability (CVSS 9.8 v3.1) affecting Udp (Arcserve).
It is exploited in the wild, listed in CIRCL KEV, Industry KEV feed since Aug 19, 2025. A public exploit is reported by tracking sources, but no code link is listed yet.
EPSS estimates a 40% probability of exploitation in the next 30 days.
Fixed versions are available, including Udp <=9.0.6034, Udp 9.0.6034.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Scores

CVSS v3.1

9.8

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

EPSS (30-day exploit likelihood)

40%

Higher than 98.6% of all scored CVEs

Exploit maturity

Exploited (KEV)

ATLAS score

51/100

Publication score, see How it works

Exploitation Verdict

KEV listed

Aug 19, 2025

778 days after publication

Federal due date

None

No federal due date

Ransomware use

Not reported

Attributed actors

None named

Exploit & Defence Guidance

Exploit maturity

Exploited (KEV)

Public exploit code

Proof-of-concept links

In-the-wild evidence

Reports of active use

Description

Arcserve UDP through 9.0.6034 allows authentication bypass. The method getVersionInfo at WebServiceImpl/services/FlashServiceImpl leaks the AuthUUID token. This token can be used at /WebServiceImpl/services/VirtualStandbyServiceImpl to obtain a valid session. This session can be used to execute any task as administrator.

Known-Exploited Catalog Listings

Catalog	Added	Remediation due	Ransomware use
CIRCL KEV	Aug 19, 2025	n/a	Not reported
Industry KEV feed	Aug 19, 2025	n/a	Not reported

Affected Products

1 affected entries in total

Product	Affected versions	Fixed in
UdpArcserve	See advisory	9.0.6034

Patched Releases

Udp

<=9.0.6034

Timeline

Publicly disclosed
Jul 3, 2023
Last updated
Nov 25, 2024
Added to CIRCL KEV
Aug 19, 2025
Added to Industry KEV feed
Aug 19, 2025

Weakness Type

CWE-863 Incorrect Authorization

References

8 more references in the full CVE brief

FAQ

Common Questions.

Arcserve UDP through 9.0.6034 allows authentication bypass.
Affected: Udp (Arcserve). The full list is in the CVE brief.
It is exploited in the wild, listed in CIRCL KEV, Industry KEV feed since Aug 19, 2025.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
A public exploit is reported by tracking sources, but no code link is listed yet.
Fixed versions are available, including Udp <=9.0.6034, Udp 9.0.6034.
Brandefense priority: patch immediately, because it is listed as exploited in the wild.

Is CVE-2023-26258 On Your Attack Surface?

Brandefense matches it against the products discovered on your perimeter and opens a finding the day a CVE like this is listed.