CVE-2016-6263 · cross-distro fix matrix

CVE-2016-6263: The stringprep_utf8_nfkc_normalize function in lib/nfkc.c in libidn before 1.33 allows context-dependent attackers to cause a denial of service (out-of-bounds read and crash) via crafted UTF-8 data.

Affects 8 Linux releases across 8 (distro × package) combinations.

Fix per ecosystem

Each block below is a distro release where CVE-2016-6263 has a known fix. Run the listed command on that distro to remediate.

Debian bullseye

Source: Debian Security Tracker

libidn→ fixed in1.33-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y libidn
```

Debian bookworm

Source: Debian Security Tracker

libidn→ fixed in1.33-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y libidn
```

Debian trixie

Source: Debian Security Tracker

libidn→ fixed in1.33-1urgency: not yet assigned
```
sudo apt-get install --only-upgrade -y libidn
```

Alpine v3.20

Source: Alpine secdb

libidn→ fixed in1.33-r0
```
apk update && apk add --upgrade libidn
```

Alpine v3.21

Source: Alpine secdb

libidn→ fixed in1.33-r0
```
apk update && apk add --upgrade libidn
```

Alpine edge

Source: Alpine secdb

libidn→ fixed in1.33-r0
```
apk update && apk add --upgrade libidn
```

Alpine v3.18

Source: Alpine secdb

libidn→ fixed in1.33-r0
```
apk update && apk add --upgrade libidn
```

Alpine v3.19

Source: Alpine secdb

libidn→ fixed in1.33-r0
```
apk update && apk add --upgrade libidn
```

Are YOU affected by CVE-2016-6263?

5-second check on your actual server. Reads /etc/os-release, uname -r, and the distro's package manager; matches against this same cross-source index live.

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