Reminds me of one of the Chickweeds - Stellaria sp.

Euphorbia?

Euphorbia terracina? Are there more narrow leaves on the lower parts of the plant? Any whorled leaves?

Jay, I think you nailed it. Attaching link to the plant entry on the largest wildflowers site. Luckily it has an English version, though smaller than the Hebrew one.

https://www.wildflowers.co.il/english/plant.asp?ID=1177

Yes, it says terracina is an agressive weed in Israel. Over here it's Euphorbia maculata that fills that role.

We have it here too.

https://www.wildflowers.co.il/hebrew/plant.asp?ID=1489

I've seen it around. Thanks! I got to learn two new names today!

Ooops. The English language page

https://www.wildflowers.co.il/english/plant.asp?ID=1489

Oops #2: I think it might be peplus, having roamed the wildflowrr site for a while.

https://www.wildflowers.co.il/english/plant.asp?ID=1219

Tetrachina grows in light soil according to the site, whereas peplus grows in heavy soils, well watered gardens - that's my garden all right. Plus peplus seems to have rounder leaves.

That's why I asked about the leaves. I wasn't totally sure.

My bad, but night had already fallen and I'm scared of the dark :)

It's an annual, so undoubtedly peplus. Thanks!