CVE-2025-0665: libcurl would wrongly close the same eventfd file descriptor twice when taking
down a connection channel after
52
This week
HIGH 7.0REMOTEDOWNGRADEMITIGATEMITIGATE
CVE-2025-0665 is a high-severity flaw (CVSS 7.0) affecting curl, bootstrap os, h300s firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
libcurl would wrongly close the same eventfd file descriptor twice when taking
down a connection channel after having completed a threaded name resolve.
Why this priority
High severity
Public exploit reference
Remotely exploitable, no login, no user action
No fix is published yet: follow the downgrade or mitigation steps.
Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.
After downgrade
Restart the service, and keep the package held until a fixed release ships.
netapp bootstrap os MITIGATE
Affected: all versions
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
netapp h300s firmware MITIGATE
Affected: all versions
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
netapp h410c firmware MITIGATE
Affected: all versions
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
netapp h410s firmware MITIGATE
Affected: all versions
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
netapp h500s firmware MITIGATE
Affected: all versions
Fixed in: no fixed release known
Safe to downgrade to: no unaffected older release
Check your OS release
cat /etc/os-release; uname -r
Debian / Ubuntu
sudo apt update && sudo apt full-upgrade
RHEL / Amazon Linux / Fedora
sudo dnf upgrade --refresh
Windows
Install the latest cumulative update from Windows Update
If no patch exists yet
OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.
Verify at the official sourceNVD · CVE Program · Report a problem with this page Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.
Quick answers
How do I fix CVE-2025-0665?
curl: downgrade or apply the listed mitigation; bootstrap os: mitigate or apply the listed mitigation; h300s firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.
Is CVE-2025-0665 being exploited?
CVE-2025-0665 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.
What does CVE-2025-0665 affect?
CVE-2025-0665 affects curl, bootstrap os, h300s firmware. Severity is high (CVSS 7.0). libcurl would wrongly close the same eventfd file descriptor twice when taking
down a connection channel after having completed a threaded name resolve.
How urgent is CVE-2025-0665?
Priority 52/100. High severity; Public exploit reference; Remotely exploitable, no login, no user action
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