CVE-2023-3255: Qemu: vnc: infinite loop in inflate_buffer() leads to denial of service
Vulnerability summary
CVE-2023-3255 is a medium (CVSS 6.5) Loop with Unreachable Exit Condition vulnerability in fedoraproject fedora. EPSS estimates a 1.89% chance of exploitation in the next 30 days, higher than 79.5% of scored vulnerabilities.
Not severe (CVSS 6.5, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Advisory lineage
Upstream 0 · Downstream 7 · Related 4Timeline
- 13-09-2023PublishedVulnerability first disclosed.
- 01-11-2026Last modifiedVulnerability information updated.
Description
A flaw was found in the QEMU built-in VNC server while processing ClientCutText messages. A wrong exit condition may lead to an infinite loop when inflating an attacker controlled zlib buffer in the `inflate_buffer` function. This could allow a remote authenticated client who is able to send a clipboard to the VNC server to trigger a denial of service.
CVSS metrics
4 scores · 4 sources · 1 version- OSV · UbuntuEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- OSV · DebianEcosystem advisory · calculated6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
- NVDNIST6.5MediumCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
EPSS trend
Probability
1.89%
Chance of exploitation in the next 30 days
Percentile
80%
Versus all other CVEs
30-day change
No change 0.00 pp
From 1.89% on 04-10-2026
Known exploited
Compare KEV catalogs
CISA KEVNot in the CISA KEV catalog.
ENISA CNWNot in the ENISA CNW catalog.
CIRCLNot in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.
Debian1 product
- qemu< 1:7.2+dfsg-7+deb12u2 | < 1:8.0.4+dfsg-1
Fedoraproject1 product
- fedoraEOL38
Opensuse1 product
- qemu&distro=openSUSE Tumbleweed< 8.0.3-2.1
Qemu1 product
- qemu≤ 8.0.3
Redhat1 product
- enterprise_linux8.0 | 9.0
Ubuntu1 product
- qemu< 1:6.2+dfsg-2ubuntu6.16
6 vendors · 6 products
References
12 links- bugzilla.redhat.com/show_bug.cgi?id=2218486Issue TrackingX Refsource REDHATPatchThird Party Advisory
- security.netapp.com/advisory/ntap-20231020-0008/X Transferred
