Skip to content

fix(isBase64): simplify padding RegExp to prevent stack overflow #2574

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
merged 2 commits into from
Aug 27, 2025
+4 −2
Merged

fix(isBase64): simplify padding RegExp to prevent stack overflow #2574

Changes from all commits
Commits
Show all changes
2 commits
Select commit Hold shift + click to select a range
e947d6f
#2491 #2573 Simplify isBase64 to prevent stack overflow
Jul 14, 2025
12211ff
Merge branch 'master' into master
rubiin Aug 27, 2025
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
6 changes: 4 additions & 2 deletions src/lib/isBase64.js
View file
Open in desktop
Original file line number Diff line number Diff line change
@@ -1,9 +1,9 @@
import assertString from './util/assertString';
import merge from './util/merge';

const base64WithPadding = /^(?:[A-Za-z0-9+/]{4})*(?:[A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=|[A-Za-z0-9+/]{4})$/;
const base64WithPadding = /^[A-Za-z0-9+/]+={0,2}$/;
const base64WithoutPadding = /^[A-Za-z0-9+/]+$/;
const base64UrlWithPadding = /^(?:[A-Za-z0-9_-]{4})*(?:[A-Za-z0-9_-]{2}==|[A-Za-z0-9_-]{3}=|[A-Za-z0-9_-]{4})$/;
const base64UrlWithPadding = /^[A-Za-z0-9_-]+={0,2}$/;
const base64UrlWithoutPadding = /^[A-Za-z0-9_-]+$/;

export default function isBase64(str, options) {
Expand All @@ -12,6 +12,8 @@ export default function isBase64(str, options) {

if (str === '') return true;

if (options.padding && str.length % 4 !== 0) return false;

let regex;
if (options.urlSafe) {
regex = options.padding ? base64UrlWithPadding : base64UrlWithoutPadding;
Expand Down