CVE-2026-40170 · cross-distro fix matrix

CVE-2026-40170: Zou Dikai discovered that ngtcp2 serialized peer transport parameters into

Affects 8 Linux releases across 32 (distro × package) combinations. First disclosed: 2026-05-25.

Fix per ecosystem

Each block below is a distro release where CVE-2026-40170 has a known fix. Run the listed command on that distro to remediate.

Ubuntu jammy

Source: Ubuntu USN

ngtcp2→ fixed in0.1.0+dfsg-1ubuntu0.1~esm1USN-8300-1
```
sudo apt-get install --only-upgrade -y ngtcp2
```
libngtcp2-0→ fixed in0.1.0+dfsg-1ubuntu0.1~esm1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-0
```
libngtcp2-crypto-gnutls-dev→ fixed in0.1.0+dfsg-1ubuntu0.1~esm1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-crypto-gnutls-dev
```
libngtcp2-crypto-gnutls0→ fixed in0.1.0+dfsg-1ubuntu0.1~esm1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-crypto-gnutls0
```
libngtcp2-dev→ fixed in0.1.0+dfsg-1ubuntu0.1~esm1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-dev
```
ngtcp2-client→ fixed in0.1.0+dfsg-1ubuntu0.1~esm1USN-8300-1
```
sudo apt-get install --only-upgrade -y ngtcp2-client
```
ngtcp2-server→ fixed in0.1.0+dfsg-1ubuntu0.1~esm1USN-8300-1
```
sudo apt-get install --only-upgrade -y ngtcp2-server
```

Ubuntu noble

Source: Ubuntu USN

ngtcp2→ fixed in0.12.1+dfsg-1+deb12u1build0.24.04.1USN-8300-1
```
sudo apt-get install --only-upgrade -y ngtcp2
```
libngtcp2-9→ fixed in0.12.1+dfsg-1+deb12u1build0.24.04.1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-9
```
libngtcp2-crypto-gnutls-dev→ fixed in0.12.1+dfsg-1+deb12u1build0.24.04.1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-crypto-gnutls-dev
```
libngtcp2-crypto-gnutls2→ fixed in0.12.1+dfsg-1+deb12u1build0.24.04.1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-crypto-gnutls2
```
libngtcp2-dev→ fixed in0.12.1+dfsg-1+deb12u1build0.24.04.1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-dev
```
ngtcp2-client→ fixed in0.12.1+dfsg-1+deb12u1build0.24.04.1USN-8300-1
```
sudo apt-get install --only-upgrade -y ngtcp2-client
```
ngtcp2-server→ fixed in0.12.1+dfsg-1+deb12u1build0.24.04.1USN-8300-1
```
sudo apt-get install --only-upgrade -y ngtcp2-server
```

Ubuntu questing

Source: Ubuntu USN

ngtcp2→ fixed in1.11.0-1+deb13u1build0.25.10.1USN-8300-1
```
sudo apt-get install --only-upgrade -y ngtcp2
```
libngtcp2-16→ fixed in1.11.0-1+deb13u1build0.25.10.1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-16
```
libngtcp2-crypto-gnutls-dev→ fixed in1.11.0-1+deb13u1build0.25.10.1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-crypto-gnutls-dev
```
libngtcp2-crypto-gnutls8→ fixed in1.11.0-1+deb13u1build0.25.10.1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-crypto-gnutls8
```
libngtcp2-dev→ fixed in1.11.0-1+deb13u1build0.25.10.1USN-8300-1
```
sudo apt-get install --only-upgrade -y libngtcp2-dev
```
ngtcp2-client→ fixed in1.11.0-1+deb13u1build0.25.10.1USN-8300-1
```
sudo apt-get install --only-upgrade -y ngtcp2-client
```
ngtcp2-server→ fixed in1.11.0-1+deb13u1build0.25.10.1USN-8300-1
```
sudo apt-get install --only-upgrade -y ngtcp2-server
```

Ubuntu resolute

Source: Ubuntu USN

ngtcp2→ fixed in1.16.0-1ubuntu0.1USN-8300-1

sudo apt-get install --only-upgrade -y ngtcp2

libngtcp2-16→ fixed in1.16.0-1ubuntu0.1USN-8300-1

sudo apt-get install --only-upgrade -y libngtcp2-16

libngtcp2-crypto-gnutls-dev→ fixed in1.16.0-1ubuntu0.1USN-8300-1

sudo apt-get install --only-upgrade -y libngtcp2-crypto-gnutls-dev

libngtcp2-crypto-gnutls8→ fixed in1.16.0-1ubuntu0.1USN-8300-1

sudo apt-get install --only-upgrade -y libngtcp2-crypto-gnutls8

libngtcp2-crypto-ossl-dev→ fixed in1.16.0-1ubuntu0.1USN-8300-1

sudo apt-get install --only-upgrade -y libngtcp2-crypto-ossl-dev

libngtcp2-crypto-ossl0→ fixed in1.16.0-1ubuntu0.1USN-8300-1

sudo apt-get install --only-upgrade -y libngtcp2-crypto-ossl0

libngtcp2-dev→ fixed in1.16.0-1ubuntu0.1USN-8300-1

sudo apt-get install --only-upgrade -y libngtcp2-dev

Debian bookworm

Source: Debian Security Tracker

ngtcp2→ fixed in0.12.1+dfsg-1+deb12u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y ngtcp2
```

Debian trixie

Source: Debian Security Tracker

ngtcp2→ fixed in1.11.0-1+deb13u1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y ngtcp2
```

Alpine v3.20

Source: Alpine secdb

ngtcp2→ fixed in1.5.0-r1
```
apk update && apk add --upgrade ngtcp2
```

Alpine edge

Source: Alpine secdb

ngtcp2→ fixed in1.22.1-r0
```
apk update && apk add --upgrade ngtcp2
```

Are YOU affected by CVE-2026-40170?

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