Vikunja veans before 2.7.1 HTTPS to HTTP Downgrade in Server Discovery
Affects all veans versions before 2.7.1, which has no tagged release, when server discovery is given an https:// URL or bare hostname. Fixed in 2.7.1.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 2.7.1
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. veans versions before 2.7.1 (all veans versions, no tagged release) User enters an explicit https:// URL or a bare hostname during server discovery, which adds http candidates Attacker is on-path and blocks the HTTPS ports so discovery falls back to HTTP
- Last modified
- FIRST's estimate of the chance attackers exploit it in the next 30 days, updated daily.What do these mean? →
- 0.16% · 4th percentile
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 20/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
Summary
Vikunja veans, a tool for setting up Vikunja server connections, is affected by a flaw that lets a network attacker positioned on the traffic path force a connection from HTTPS down to plain HTTP during initialization and login. Because the attacker can exploit this remotely without logging in and only when a user takes an action, they could capture passwords, TOTP codes, or bot tokens and read API traffic in cleartext.
Read the original description
Vikunja veans before 2.7.1 contains a protocol downgrade vulnerability in serverCandidates that allows on-path attackers to force plain HTTP during veans init and login. Attackers can block HTTPS ports so discovery accepts an unverified HTTP response, capturing passwords, TOTP codes or bot tokens and persisting cleartext API traffic.
cve.now Index
- Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
- Exposure12/25Specific setups only, reachable over the network without a login
- Reach?/20Unknown. No tracked technology or package matched
- Severity7.6/10CVSS 7.6
- No patch0/5No signal
What would change the score
- Would score about 70 if added to CISA KEV
- Would score about 65 if CISA's SSVC rates exploitation active
What to do
Check whether your setup matches what the bug needs.
veans versions before 2.7.1 (all veans versions, no tagged release) User enters an explicit https:// URL or a bare hostname during server discovery, which adds http candidates Attacker is on-path and blocks the HTTPS ports so discovery falls back to HTTPUpgrade to a fixed version: 2.7.1.
Timeline
- CVE published
- First seen by cve.now
Affected versions
- go-vikunja vikunja
fixed in 2.7.1
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-123497
Is CVE-2026-123497 being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data
What does this mean?
An on-path attacker who blocks the HTTPS ports makes server discovery fall back to plain HTTP. This can expose the user's password, TOTP code or token, and API traffic sent in cleartext.Source: github.com, vulncheck.com
Which versions are affected by CVE-2026-123497?
vikunja: before 2.7.1.Source: cve.now feed data
Am I affected, and how do I check?
All veans versions before 2.7.1 are affected, since veans has no tagged release. The issue applies when server discovery gets an explicit https:// URL or a bare hostname, which adds HTTP candidates. To check, compare the veans build against 2.7.1 and note whether server discovery is used.Source: github.com, vulncheck.com
How do I fix CVE-2026-123497?
Upgrade to Vikunja 2.7.1 or later, which contains the fix.Source: github.com, vulncheck.com